Abstract: The paper aims to improve the short-term forecasting capability of rainstorm in Fushun. The author used automatic stations’ observation data, radiosonde data and NCEP reanalysis data, analyzed the rainstorm process on July 9, 2013 and August 16, 2013 in Fushun. The results showed that the two events occurred in the zonal westerly airflow circulation pattern, the cold air of Lake Baikal at 500 hPa which moved to the southeast was the main cause of rainstorm in Fushun Region. But the difference was the cold air delivery form, "07.9" rainstorm was caused by the southeastward ridge from Lake Baikal, "8.16" torrential rain process was mainly caused by horizontal trough from Lake Baikal. There was a very strong upper-level jet stream at 200 hPa in the two rainstorm processes, but their upper-level jet stream diversion district positions were different. The jet stream diversion of "8.16" torrential rain process began from the western boundary in Liaoning, thus contributing to the occurrence of torrential rain. Low-level jet, diversion district position of upper-level jet stream and ground system were the direct causes of the rainstorm intensity difference.