Abstract: The characteristics about VWP during two different properties of heavy rainfall events on Xining radar are analyzed, the results show that the wind speed of SW at the lower level increases, ND appears at the middle level and the E-flow at the high level is obvious before the beginning of heavy precipitation in Xining. The maximum precipitation in the process occurs during the period when the wind direction at the low level changed significantly. The heavy precipitation begins or increases when highlevel strong air flow are transmitted downward to the low level and it is biased to the right of the upper airflow during the mixed heavy rainfall event, while the low-level strong airflow mainly transmitted downward and the bias amplitude to the right is smaller during the convective heavy rainfall event, and the appearing of ND wedge block at the middle level is a harbinger of the heavy precipitation.