I will have an interview soon with a professor from the Graduate Committee. I checked his CV and found he is also from China. He said he would set an interview soon with me to help the Committee make a decision on my application. What do I need to prepare?? My Senior Project?? or anything else?? Will we just talk in Chinese or English ??
You should use english I think. That's part of the issue about TA position. They are not sure about your level of spoken english.
Review your personal statement as you submitted during online application.