Abstract: By using the observation data of automatic ground stations, high sounding data, NCEP reanalysis data and FY-2G satellite TBB data, the genetic mechanism as well as TBB and vertical helicity characteristics of a rainstorm process caused by MCC in the south of Panxi area is analyzed. The results show that the rainstorm process was caused by the combined influence of South Asian high atmospheric pressure, high-level trough and shear line; MCC occurred in the unstable stratification of high energy, high temperature and high humidity, and heavy rainfall mainly occurred in the low-TBB-value area and high-gradient-value area, and the moving direction of MCC was basically consistent with that of heavy rainfall; the configuration of vertical helicity with negative upper layer and positive middle and lower layer was beneficial to the occurrence of rainstorm, and the greater the central value of vertical helicity, the greater the rainfall intensity; the vertical helicity at altitude of 700hPa had a good correspondence with the shear line and the convergence center of water-vapor flux in the next 6 hours, which had certain indication action on the rainfall in the next 6 hours.