Is it possible to transfer out of Miami International Airport in one and a half hours?

No matter which airport you are transiting through in the United States, there are no customs procedures except for the possibility of changing terminals and the possibility of going through security again. Especially if it is a connecting ticket, the checked baggage has been checked in at the original airport to the final destination, and boarding passes for each section have been collected at the same time. As long as the person gets off the plane at the connecting airport and goes to the next flight terminal and boarding gate, the airline will Check your passport/visa and boarding pass at the airport, get on the plane and fly. An hour and a half is definitely enough for you. During the departure process from China, you have to go through security inspection, border inspection (document inspection), and customs (substance inspection). When leaving the United States, you do not go through border inspection (Immigration), let alone customs.