Hi ChenyuLue and thanks for this essay.

Introduction

Your introduction is fine. You start with an example or a definition which shows clearly that you understand the terms in the question. Your second sentence is a bit awkward: you wrote:

Whether multi-culture is beneficial or detrimental has not reached the consensus.

Here’s one possible rewrite:

Whether multicultural societies have more problems or strengths than monocultural ones is a difficult question to answer. OR

There is no consensus on whether multicultural societies have more problems or strengths than monocultural ones.

There's no need to have a debate/contentious issue/spark/heated/controversy/discussion for every IELTS topic. You can get around this by giving examples:

Many countries in Europe for example have undergone huge changes in society with the arrival of new immigrants and settlers.   OR

Many countries struggle to define what nationality means. 

You've used 'multi-culture' throughout -  this is not correct. Use the adjective 'multicultural' or use a synonym.

Avoid generalizations like 'always'  (Paragraph Two). Have a look at the official descriptors for IELTS Task 2 Writing (public version) here, under Task response and look for the word generalise. It's easy to avoid -  just use the word 'often' or 'frequently' or use a modal -  can/may/might 

• Because of this, another detriment occurs  → problem

Specify

You wrote:

• each culture has its own advantages and disadvantages

This is not the correct word choice, particularly in our politically correct world, and you also need to give an example. We are not really supposed to say that “One disadvantage of French people is X” or a “major disadvantage of Vietnamese people is Y.” 

Ideas

Your third point in Paragraph Three, about music and dance, is quite similar to your second point. Try to have a range of quite distinct ideas.

Conclusion
Your conclusion is very long, with 46 words. I recommend breaking conclusions into two or three sentences. Try to reduce your average sentence length to about 12-15 words. Add a few short sxentences

Transitions and Linking Words

I'm quite happy with your use of linking words and transitions -  they seem quite natural to me, especially in the second and third paragraphs. It's only in the introduction and the conclusion that your wording is a little awkward, as DavidLee has spotted -  well done!

I like the discussion: it's all about balance. Of course we need some linking words and transitions, but we just have to be careful not to overuse them. I think your balance is good, but perhaps in the intro and conclusion you could feel freer to write/use your own structures.  

Your punctuation is good too -  I would recommend simple full stops to most writers, but you've used the semicolon well.

I like most (not all!) of DavidLee's suggestions -  he spotted some good things. His best comment is on the conclusion: I think if you had more ideas and examples in the body, the conclusion would be more interesting.

What about:

• cultures and tourism (visitors, festivals, heritage, museums)
• cultures and different ways of thinking
• cultures and language (poetry, writing, literature, communications)
• cultures and education (cost, headaches, two languages, language policy)
• cultures and equality (politics, equal rights, clothes, separate schools)
• cultures and development (education, employment, division of resources, division of national budget)

Some more specific examples would be good. Thailand? USA? China? Malaysia? Australia? Paris? South Korea?