Abstract: This article introduces the overview and seismic geological characteristics of the M_S5.5 earthquake in Pingyuan, Shandong.Elaborates in detail on the rapid response and disposal capabilities after the earthquake mobile gravity and mobile geomagnetic emergency observations, and conducts encrypted observations after the earthquake. It analyzes the changes in gravity and magnetic data before and after the earthquake, The main use of mobile gravity data in recent years was to systematically analyze the dynamic evolution characteristics of the half year scale difference change and the 1-3 year scale cumulative change of the gravity field before the M_S5.5 earthquake in Pingyuan. It better reflects the abnormal precursor information of the rapid increase in mobile gravity during the development and occurrence of the M_S5.5 magnitude earthquake in Pingyuan, and the effective theory of reverse recovery of the gravity field after the earthquake. Finally, the emergency observation results of mobile gravity and magnetism were analyzed, and the mechanism between gravity field, stress field, and earthquake relationship was discussed. Through post earthquake emergency observation and analysis, we should continue to strengthen the ability of gravity and magnetic fusion analysis, improve the reliability of the analysis results, provide feasible basis for subsequent observation and further analysis and judgment after the earthquake, and also provide reference basis for post earthquake summary and further strengthening of mobile monitoring and earthquake risk zone identification in Shandong region.