Taking the 2020’s M5.6 earthquake in Shiqu, Sichuan, as an example, the authors use RISP system to retrospectively analyze the earthquake sequence, and obtains a relatively reliable earthquake sequence catalog, which is compared with the manual catalogs.Results: Within 10 days after the main shock, 386 automatic catalogs were automatically processed by the RISP system. The number of automatic catalogs is 1.98 times that of manual ones, and the matching rate is 97.43%. Compared with the manual catalogs, the 71.05% of origin time differences are less than ±1.0 s, the 96.31% of epicentral differences are less than 10 km, and the 9947% of magnitude differences are less than ±0.3. Based on the distribution characteristics of the earthquake sequence detected by RISP and the focal mechanism solution, the seismogenic fault of this earthquake is considered to be an undiscovered branch fault on the northeast side of the Wudaoliang—Changsha Gongma fault. Conclusions: This study shows that the application of the RISP system can improve the seismic detection capabilities in sparse areas of the seismic network, and it can quickly produce a catalog of earthquake sequences, which is of great significance for major earthquake emergency response, postearthquake trend determination, and seismogenic structure research.