Abstract: In order to analyze the primary causes of a regional rainstorm in Shanxi Province, based on the data of conventional and unconventional weather observation and monitoring, the regional rainstorm weather process occurred in Shanxi on July 1-3, 2011 was analyzed form the large scale circulation background, low-level affect system, infrared satellite cloud picture, the spatial vertical section of unstable energy and physical quantities field. The results showed that: the rainstorm occurred in the circulation background of east-high and west-low subtropical high affects, low-rise shear became rainstorm major effects stem, strong upward movement, low convergence and high divergence flow field configuration provided favorable dynamic conditions for the heavy rain, vorticity field was consistent with the changes of the high-low air system in time and space distribution, ki index ≥32℃, si<0℃ unstable regions in the precipitation period was always consistent with low-rise shear system in place, promoted the generation of the persistent heavy rain.