Hainan Island is a relatively independent block located in the southern part of the South China Block. There exist many viewpoints for its origin. This paper is based on the systematic analysis of many pieces of evidence such as geographic geomorphology, strata, fault zone, magmatic rock, ore belt distribution, seismic exploration profile, paleontology, and genesis of three basins surrounding Hainan Island. The results show that Hainan Island was separated from Beibu Gulf and rotated about 150℃ounterclockwise from the original position to the current position. The starting time for the separation is about 65 Ma, and the main rotation drift occurred at 40-24 Ma. At present, it is still drifting toward the southeast and is accompanied by counterclockwise rotation. The genesis of Hainan Island is closely related to the collision process between the Indian Plate and the Eurasian Plate. The dynamic mechanism is that the large-scale extrusion and rotation of the Indochina block has driven Hainan Island's fission and rotation drift from South China. This study provides remote constraints for the structural evolution of the collision process. At the same time, it also has certain guiding significance for the study of the metallogenic belt in Hainan Island.