Abstract: Downhole microseismic monitoring technology can help determine the hydraulic fracture propagation direction, length and formation crack energy during shale gas well hydraulic fracturing, and thus can guide the adjustment of real-time fracturing operations and increase the fracturing volume. Therefore, downhole microseismic monitoring technology has been applied to the hydraulic fracturing operation in shale gas "well factory" on five pads of Block Wei 202 to detect fractures. The basic measurement principle of downhole microseismic monitoring technology was applied to the six wells on the platform A of Block Wei 202. The results function as a useful case study and an example, and both the mechanism and effect of the technology are evaluated in detail. The technique proved effective in identifying potential natural fractures in the formation, monitoring the effect of temporary plugging and diverting volume fracturing, and guiding perforation parameter optimization. Studies and applications showed that the downhole microseismic monitoring technology could increase the shale gas reservoir reconstruction volume, and even out the reservoir reconstruction degree, thus playing an important role in cost-effective development of shale gas.