how to get VOA in shenzhen airport? where do i should to go?

Ivan, you can just fill in an application form, submit your passport, pay RMB 168, and the officer will take a photo of you. After a few minutes, your passport will be returned with a VOA inside. You should go to the immigration desk at the airprot.

Frankly speaking, you are likely to get the VOA, but I cannot say that you will be certain to get it. So there is a chance that you may be rejected, though the chance is not big.