Abstract: Based on surface intensive observational data,automatic rainfall station data,TBB data of FY-2C satellite and reanalysis data of NCEP，the weather causes of Yunnan heavy rainfall induced by the typhoon No.1002 “Conson” and No.1003“Chanthu” entering low latitude plateau and the maintaining mechanism on the land area have been compared and analyzed.The results show that the birthplaces and the landing locations of two typhoons were different.Typhoon depression,after entered into Yunnan,besides carrying a large quantity vapor and energy itself,involved south jet flow is long subsistence.The main reason that “Conson” caused heavy rainfall in Yunnan was that the convergence of the cold and warm air over west Yunnan.The moisture convergence strengthened on the lower level after typhoon depression entered into Yunnan.The updraft appeared on the lower level in convergence area of vapor and the downdraft appeared on the higher level,which maintaining heavy rainfall.After typhoon depression entering low latitude plateau,a few mesoscale cloud cluster excited by the mountain dynamic effect that led to heavy rainfall.