A contrast analysis of two heavy rainstorm occurred in Liaocheng of Shandong Province in different seasons was made from synoptic situation，physical quantity field and radar echoes characteristic．The results show that the summer rainstorm usually accompanied by strong convective weather，mid－cyclone and adverse wind areas．When the heavy rainstorm occurred in autumn，the intensity of radar echoes was not very strong but lasted longer，and some physical quantity indexes related to heavy rainstorm were lower in autumn than those of in  auummer．The forecast of heavy rainstorm in autumn is difficult．