Abstract: By studying wind field in automatic weather station by scale separation method, combining Doppler radar in 2010, the article analyzed the rainstorm in western part of Sichuan Basin on August 18th.It shows the surface wind gradually changed from the very messy situation to regular status, which is reflected on the consistency of wind direction and the enhancement of wind speed;convection echo is generated by terrain influence.Convection echo can be enhanced in areas of meso-scale convergence line existed for a long time and areas of meso-scale positive vorticity maintained for a long time;if convection echo moves into convergence zone, it is conducive to strengthen the echo, and if strong echo moves into divergence zone, then the echo tends to be weaken.