Abstract: By using the new Doppler weather radar Guiyang CINRAD/CD basic product and sounding data,an extensive rain and snow weather process which occurred on January 9th 2015 in central and western Guizhou is analyzed in order to study the variation characteristics of Radar reflectivity,echo top height,vertical structure and radial velocity. the echo structure is filamentous,indistinct borders and does not have the area of abnormal high radar echo,the heights of echo top of the precipitation particles are relatively low. There are many features in the radial velocity,the surface layer is northeast wind with an average speed,a structure with a shape of a cow's eye which means that there existed a low-level jet,in the middle upper layer,there was cold advection in the north and warm advection in the south. The anomaly deep cold and humid air,inversion layer in the quasi stationary front and high-level southwest jet,which is favorable for the rain and snow formation and aggravation.