Based on the observation data of relative gravity in Shaanxi-Gansu-Sichuan region from the year 2016 to 2018, we analyzed the variation characteristics of gravity field at a time scale of 0.5~1 year before Ningqiang M_S5.3 earthquake. We also decomposed the Bouguer gravity anomaly in the epicentral area of Ningqiang M_S5.3 earthquake by 1~4 order wavelet, and analyzed the detail image of 1~4 order wavelet. The research results show that:① The gravity field of Ningqiang M_S5.3 earthquake displays the evolution process pattern of "positive variation-positive weakening-negative variation-negative weakening". Before the earthquake, the gravity field presents the characteristics of four quadrant distribution, and the epicenter is located in the saddle position, which implies the characteristics of strike slip earthquake. ② The 2nd to 3rd order wavelet details of Bouguer gravity anomaly have a good correlation on the seismogenic characteristics of Ningqiang M_S5.3 earthquake. The corresponding field source depth of the 2nd to 3rd order wavelet details is 10~15km, which has a good corresponding relationship with the focal depth of this earthquake.