By using Doppler Radar data,the characteristics of rainfall intensity and wind field in Xiamen caused by tropical cyclone “Beimian” are analyzed. The results show that the heavy rainfall is induced by the interaction of multi-synoptic systems,and by the convergence of southeast wind and southwest wind in low atmosphere as well as the cells' mergence. In addition,the cells' breakaway and mergence have a connection with the perturbation of the jet in low atmosphere.