you have to past MCAT, which is the admission test for medical school. I do not know whether you can do it in China. The tuition is not a problem. You can get the loan. But, the problem is interview. Usually, there are two round interviews, which have to be face to face. How can you make that? Even you can make that, how can you convince people that your english is good enough for medical school. So many American with Master degree, even PHD, still can not make that. If you really wanna do medical school in US, I suggest you do college in US again. Then, you may have chance.