Hey , I'm Adam

Hey, I'm Adam.  im I just began to using italki today. I'm a student of one of at university in China. I wanna want to learn English.  I think my oral english is not bad, but I can't write. I have had no chance opportunities to write in English. Beside , 

[I'd start a new paragraph here since you shifted topic:] 

I'm a rapper, I like hip hop music.  Is there anyone here who likes rap ?

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Welcome! 

You have some punctuation and capitalization problems, but are overall understandable. 

 [1st sentence] It's a run on, so I split it into smaller sentences. Either "I just began to (+verb)" or "I just began (verb stem+ing)".  

You are a student of someone or perhaps of something, but you are a student at a school. 

E.g. Teacher: That girl over there is a student of mine. 

"I have no chance to" -- "opportunities" works better than "chances" here. I'd also make it past tense.

Perhaps you could say "Besides that", but it's informal and not quite right.