There are many plastic surgery hospitals in Beijing, and the better double eyelid plastic surgery hospital I know in Beijing is Kyoto Fashion.

It's just over there on Beichen Road, doctor. You can go to the plastic surgery circle. I'll check the experts there. The best binocular doctor I know is Wang Zhenjun.

There are two simple methods: embedding thread and cutting. There are others, I'm not sure. You can ask the doctor.