Abstract: Based on the data of conventional observation and the NCEP reanalysis, the author used weather dynamic diagnosis methods to analyze the dynamic processes of upper- level and lower- level jet stream for Liaoning regional rainstorm on 4th- 5th August 2010. The results showed that the heavy rain occurred in the large-scale circulation situation of“East West”，the heavy rainfall occurred between the line of 584 dagpm and 588 dagpm, and the main impact system were the upper trough, the subtropical high and low-level shear line. In heavy rainfall, the upper- level jet stream’s eastward movement played an important role in the development and strengthening of the low-level jet, and could be the important driving force that caused the formation of the LLJ in Liaoning Province. The heavy rainfall occurred at the right side of entrance region of the upper-level jet and the left side of entrance region of the lower-level jet. During heavy rainfall, the descending motions occurred in the north side of the upper-level jet stream, but the sink motion occurred in the southern of the entrance area. It was noteworthy that during rainstorm, there were two low-level jets at 850 hPa, while the ascending branch of the low-level jet provided favorable dynamic conditions. The southerly moving of the sinking branch of the lower-level jet stream provided a favorable moisture conditions. During the powerful jet stream, the secondary circulation which affected rainstorm area was anti-circulation loop that ascending in the Liaoning Province and sinking in the southern of Liaoning Province; in the late stage, along with the jet stream weakened rapidly, the ascending branch of the low-level jet was in the southern of Liaoning province and the sinking branch of the low-level jet in northern Liaoning Province, which formed a Positive circulation. In this process, the presence of two low-level jet streams, the low-level jet secondary circulation just embedded in the high-altitude jet secondary circulation and the conversion of the direction of the secondary circulation were all important features of the heavy rain.