The Sichuan-Yunnan region is located at the intersection between the South China Block, the Indian plate and the Tibet Plateau and is crisscrossed with deep and large faults and is characterized by strong seismic activities. Here we employ one-year continuous waveforms of the vertical component of 89 broadband seismic stations in this region to evaluate the velocity structure and its implications. Through single station data preprocessing, cross-correlation calculation, stacking, group velocity dispersion measurement and quality evaluation, the group velocity dispersion curves of Rayleigh waves for the different periods were obtained. We then use the surface wave tomography method to obtain the Rayleigh wave group velocity distribution of 9-40s in this area. Finally, the S-wave velocity structure in the depth range of 0-60 km in the study area is obtained by pure path dispersion inversion. The results show that the surface layer or the top of the upper crust in the Sichuan Basin is characterized by low velocity due to the influence of the sedimentary strata, whereas the middle and lower crust of the Sichuan Basin shows high velocity structure. The Sichuan-Yunnan diamond-shaped block (SYDB) shows a high-velocity structure in the middle crust, , and a low velocity in the lower crust. The seismic activities are mainly concentrated at the western part of the region, with the earthquakes distributed at the boundary between the low- and high-velocity structures, as well as the adjacent region, which we correlate with the extrusion of the Tibet Plateau.