Abstract: In the report， the 2009-2020 Dongfang City encrypted automatic station data， ERA5 reanalysis data， and CLDAS atmospheric driving data， were used， the westbound or northwest tropical cyclone （TC） affecting Dongfang City were divided into four types， and the extreme precipitation were analyzed， and the typical cases were used for analyzing the causes of extreme precipitation. The results suggested that the extreme precipitation distribution of the landfall type TC from the Pearl River Delta to the Leizhou Peninsula （referred to as Route I） increases from west to east. The extreme precipitation distribution of landfall type TC， from Haikou to Wenchang （referred to as Route II）， is smaller in the north than that in the south. The extreme precipitation of landfall type TC from Qionghai to Lingshui （referred to as Route Ⅲ） showed a decreasing trend from south to north. The extreme precipitation distribution of the type TC passing by Sanya or passing offshore （referred to as Road IV） decreases from west to east. The four TC processes in Dongfang City are all accompanied by a strong vertical rising velocity， reaching more than 3 Pa·s^-1， the lower layer has a strong convergence of water vapor flux， reaching more than -25×10^-5g·cm^-2·s^-1， the low layer convergence intensity reaches more than -20×10^-5·s^-1， the up-layer divergence intensity reaches more than 25×10^-5·s^-1. The non-geostrophic wet Q-vector divergence can characterize the rainfall area and moving trend of heavy precipitation in the next 0-1 hour very well. The heavy precipitation area appears in the wet Q-vector divergence convergent zone or the junction of the wet Q-vector divergence convergence zone and divergence zone.