By using conventional observation data and NCEP 1°×1° reanalysis data, analysis on the common effect of vortex and subtropical high on rainstorm process is done. It is found that the heavy rainstorm fall area is not consistent with the vortex location and path. So, it is not always reasonable to forecast the rainstorm fall area following the location and path of vortexes. Forecasters should do some analysies on the spatial structurs of impact systems, the developing stages and the evolution characteristics of surface situation. When the impact system is frontal system, the initial convection system is often trigger by the frontal surface. Therefore, the fisrt rainstorm fall area tends to appear near the frontal suface, and then heavy rain in warm zone triggered by the cold front follows, not needing the strong dynamic convergence conditions. The heavy rains may fall far away from the vortex center, but is located in the high temperature and wet tongue on the edge of subtropical high. In addition, more attentions should be paid to the primary convective clouds on the surroundings and the heavy rain brought by the convective clouds.