A heavy rain occurred in Longyan on 18 June 2006 is analyzed by using the data of routine observation, automatic weather stations, satellite pictures, and CINRAD/SA observations. The results show that the favorable environmental condition, ample water vapor condition, strong ascending movement and the invasion of weak cold air caused the heavy rainfall. The heavy rainfall was resulted from the local mesoand smallscale systems emerging from the mesoscale landform. The CINRAD/SA data indicate that the convective cells have the typical features of severe liquid precipitation. The retrieved wind field from radar data shows that the smallscale systems such as wind speed convergence and shear lines are the causes of shortrange severe precipitation.