Both 'subject' and 'topic' can be used to refer to 'what a speech, piece of writing or artistic work is about'. Some dictionaries say 'subject' is the more general term and 'topic' is used more than 'subject' when we mean the subject matter or focus of a conversation or discourse. We would say 'English speaking topics for conversation practice' not 'English speaking subjects for conversation practice'. 'Subject' also has a number of other meanings which are not synonymous with 'topic'.

It's the same in English as it is in Chinese!

I guess the difference I can cite for you here is that there is such a thing as 'subject'-verb agreement but ypu cannot say, 'topic'-verb agreement ;)