Abstract In this paper, we study the crust-mantle transition zone structure of the south and north Songpan-Ganzi and the Yangtze plate (SSGT, BY-SG, YZB). The thickness and velocity structure of the crust-mantle transition zone of three different tectonic blocks are obtained by the receiver function method. It shows that the thickness of the transition zone of the SSGT block is 1.79-3.4 km, with an alternating velocity structure. The transition zone of the crust-mantle is getting thicker, breaking the original crust-mantle transition zone temperature and pressure conditions. Besides, it has a strong tectonic activity in the southeastern northeast, resulting in an alternating velocity structure. The thickness of the transition zone of the BY-SG block is 2.22-3.72 km, and the velocity structure is a gradual velocity structure. This block has been suffering the effects of continuous compression, gradually changing the temperature and pressure conditions of the transitional zone of the crust and mantle, forming the velocity gradient structure. The YZB block crust-mantle transition zone is 0.86-1.58 km, and the velocity structure is the velocity instantaneous structure. The crust-mantle transition zone in Sichuan basin (YZB) is a good first-order discontinuity, and the transition zone is thinner and the structure is a velocity instantaneous structure.