Abstract We correct the gravity change obtained by the vertical change rate to the gravity change of CG-5 by CORS, plot the real regional gravity field map of the Maoshan fault zone, and analyze the gravity field changes in this area. 18 relative gravity points near the Maoshan fault zone are selected for synchronous GPS-RTK measurement. We compare and analyze the measured data, and calculate the height variation of the GPS as the basis of the gravity value. On the basis of the gravity value of 2014, we correct the gravity measured values of three periods from 2016 to 2017 by the gradient variation, and draw the anomalous contour map of the gravity field to study the anomalous variation of the gravity field in the Maoshan fault zone. The results show that the contrast of the gravitational field difference diagram before the elevation correction shows that the shape of the gravity field changes greatly, and the direction of the high gradient area and the zero line are all changed. The research results are of great significance for determining the annual anomaly area based on the trend of differential variation.