Hi Colin and welcome to Writefix.

I like the way in which you are using the official descriptors for IELTS Task 2 Writing (public version) to assess your work. It's much better than relying on some old textbooks or even some teachers. 

I'm afraid I cannot give a number grade or band for each criterion, but others on the site are very welcome to do so.

Word Count

Colin, your essay at 378 words is too long.You need to remove 100 words at least. You need to cut out all standardized generic phrases, clichés and tired old phrases and sentences like these here and here. Try to avoid using these phrases! Don't use 'To recapitulate' if you can say 'In conclusion' or 'I believe.'

Simplify your writing, and get to the point.

You should aim to write between 250 and 300 or maybe 320 words - any more and you may be penalizing yourself due to rushed writing and increased errors. There is no penalty for writing more than 250, but you will be tired by the time it comes to Task 2 writing, and many most candidates who write long essays actually score lower because of mistakes in grammar or layout.

You wrote:

Over the past decades, with the changes in the social role, the females’ position in the business field, political spectrum and academic circles has improved. (25 words)

Here’s one possible rewrite:

Over the past decades, women have become more involved in business, politics and academic life.  (15 words).  

That’s a 40% reduction in just one sentence. It gives you more time and words to give your ideas.

Ideas: Not Enough

Even though you have 378 words, you only have THREE ideas:

• some women can be good at science, e.g. Marie Curie
• women and men can learn very well together because of different characteristics. You take 123 words to say this
• women cannot work on building sites.

 Don't start to write until you have SIX ideas at least -  three for, three against. Adding padding and empty phrases won't compensate. Look in the descriptors under Task Response for the phrase "Presents some main ideas but these are lmited" or "some parts are more fully covered than others'

You wrote:

The issue of whether university should admit students studying any subject regardless of gender is of great interest to sociologists. 

Where? I haven’t spoken to many sociologists recently, but the ones I do meet rarely worry about girls studying engineering or boys doing ballet.

Avoid this tired old phrase. Avoid reference to experts, psychologists, recent research, or anyone else. It’s an opinion essay, not a term paper: Give your opinion and not that of some nameless scientist or newspaper editor.

Here’s another example:

Experiments abound in psychological research

Where? Do you have the references?  There’s no need.  Your first sentence is fine: “Undeniably, female students are capable of achieving distinction ….”

Pronoun Reference

You wrote

This admission criterion, from my perspective, should not be taken so rigid, and the college girls should be given sufficient in learning most of subjects.

What 'criterion'? Sufficient 'what'? Colin, we are 70 words into the essay (more than quarter way in to the requirement of 250 words) and we still don’t know what you are going to discuss.  Here it is in simple English:

Should colleges have equal numbers of women and men in every subject? OR 

Should an equal number of men and women be enrolled in all subjects?   OR 

Should  university courses have equal numbers of male and female students?

Pronoun Reference 2

You wrote:

To recapitulate, I agree with the argument that in some particular majors, admission officers should be accepted females with cautions.

Which argument? Why cautions?  Should they sign?  Colin, you need to be specific and avoid unclear pronoun reference. You have changed the topic here - make sure you don't go off-topic.

Neither nor…

Avoid this structure. Avoid ‘not only/but also.’ Use simple, clear sentences. Have a mix of short (4-8 word) and long (9-20 word) sentences. You wrote:

Nevertheless, neither should we ignore the potentials of females in academy, nor should individuals neglect the contributions of females in class. (21 words)

Which individuals? What does ‘academy’ mean? What is the reference? Have a look in the descriptors under Coherence and Cohesion for the phrase "may not always use referencing clearly or appropriately."  Simplify! Nobody uses this structure any more. 

Here’s one possible rewrite:

We should recognize the potential of women in university. (9 words)   OR 

Universities should work to attract more women (7 words).

However, it’s now off topic. The question is not about cautions -  it’s about whether universities should have equal numbers of male and female students in their classes.

Word Choice/Word Form/Usage

• Undeniably, Female students are capable of achieving distinction in the majority of curriculums. → Undeniably, Female students are capable of achieving distinction in the majority of subjects.

Shorten/Simplify

You wrote:

Furthermore, either female or male students can complementary to each other while studying together. In case studies or group discussions, for example, female students have personality advantages of such interpersonal skills as cooperation ability and persuasion ability, compared with that of male. Consequently, the each student can cooperate with each other effectively and efficiently, taking advantage of different characteristics and strengths, in teamwork. Similarly, the innovative ideas can be sparked frequently and effortlessly in brainstorms. Most essentially, male students usually conduct a tough stance because of their aggressive and combative personality. By contrast, females tend to pay attention to the decision-making process with full consideration. As a result, the joint group of males and females would be an excellent complement in group research. (123 words),.

Here's a possible rewrite

Furthermore, male and female students complement each other in class. In case studies or group discussions, for example, female students cooperate and persuade more than men. By using different characteristics both learn better together. (34 words)

Generalizations

You wrote:

Taking the course of construction engineering for example, it demands fist-hand practice in the real construction sites, such as buildings, bridges, and even underground tunnels. If this class admitted females, Physical injuries and mental stress would be happened in female students frequently and inevitably.

Here, Colin, you have probably alienated half your readers, both here and the nice patient lady who may mark your IELTS paper. There are many women working as engineers worldwide - and as roadbuilders and as laborers on construction sites. And only last week a female astronaut from China performed a very difficult and demanding manual docking of an entire space craft.

Avoid obvious generalizations: most female architects and engineers do not collapse into uncontrollable sobbing or trip on their high heels the moment they enter a building site.

(Of course, even if the examiner is nice, or even a lady, she will not be affected by your ideas in any way, and will not let them affect her opinion of your essay as long as they are adequately supported.)  

Overall

Colin, I think you can write, but you are being held back by trying to use a style which is far too complicated and wordy. Just say what you need to say and get on with it. Have SIX ideas, not three, and develop them fully but without repetition.  In grammar, you make "some errors in grammar and punctuation but they rarely reduce communication" while in vocabulary, you use an "adequate range of vocabulary for the task" and ƒattempt to use "less common vocabulary but with some inaccuracy."  The big weaknesses are in Task Response (not enough ideas, some overdeveloped and rambling) and Coherence and Cohesion: pronoun reference, links between sentences, overlong paragraphs, progression is not always clear.) 

If you throw out all the standardized phrases and just write 250-275 words in simple clear English you will be fine. And the nice lady who marks your IELTS paper will not wish that she had become a civil engineer.