How can I apply to college without a GPA?

You should finish HS, or get an equivalent certification. In the US, students who drop out of HS can take a GED test which many colleges will accept in lieu of graduating HS. Does China have something like that?

Some US community colleges also require the student to have completed HS/or have passed the GED, you would have to do some research on that. Are you thinking of coming to the US for college? If so, will you be able to afford that?