Abstract: To evaluate the application ability of Fengyun satellite in typhoon rainfall forecasting , short-time/ nowcasting and warning , the ERA5 hourly reanalysis data of European Centre for Medium-Range Weather Forecasts (ECMWF) is used to analyze a heavy rainstorm process caused by a typhoon spiral cloud system in Hunan on July 18 , 2023 . The results denote that :1) This heavy rainstorm was caused by the spiral cloud system of Typhoon Talim that landed westward and northward . The upper-air circulation was a two-trough , two-ridge pattern . The adequate water vapor and dynamic conditions provided favorable ambient conditions for triggering meso- and small-scale rainstorm clouds . 2) There was an obvious typhoon eye when Typhoon Talim landed . Affected by the typhoon spiral cloud system , white-bright convective cloud clusters appeared in Hunan on the afternoon of July 18 , and they continuously developed into mature cumulonimbus clouds , leading to the heavy rainstorm process . 3 ) During the rainstorm , the maximum coverage area of mesoscale convective system ( MCS) reached 4 , 000 km2 , the minimum convective brightness temperature was 188 K , and the minimum temperature lapse rate dropped to - 19 . 8 K/5 min . The changes in the parameters of quantitative indicators of MCS can better monitor the developing trend of heavy rainfall , and have certain advance indication significance for the process of heavy rainfall . This research proves that Fengyun satellite can accurately analyze the evolution characteristics of typhoon and rainstorm systems , and is undoubtedly a technical support for short-time/nowcasting and early warning operations .