In the paper, R-component receiver functions of P-wave under 12 stations in Sichuan(MEK,YZP,JJS,ZJG,YTS,GDS,XJP,MDS,EMS,WMP,YGD,HMS) were calculated from 3-component broad-band digital recording data of 57 distant earthquakes. Additionally, the moveout correction technique in exploration seismology was introduced to correct the receiver functions to the 67° reference epicentral distance. Then the receiver functions were stacked to punctuate signals, and the stacked functions were used as the mean receiver functions under stations. Finally, the mean receiver functions were used to invert for the S-wave velocity structures under stations. Results showed that the depth of Moho in the west of the Jinpingshan-Longmenshan fault is as thick as 70 km, but only 50 km in the east, indicative of a sharp discontinuity. The crustal velocity structure in the western Sichuan is different from the structure in the middle of Sichuan, in that a low-velocity layer of 8~22 km exists in the middle-crustal beneath the western Sichuan. The thickness of the low-velocity layer is the largest in the region of Dujiangyan and Ya′an, between 20 km and 22 km. The upper crustal in this region behaves as a firm solid, forming the seismogenic background under the action of the regional tectonic stress field.