Abstract: Based on the calculation theory of gravity terrain correction of spherical shell model，explored the effect of horizon deviation and flat-plate model not accounting for Earth's curvature on gravitational ground modification, studied the relationship between the accuracy of gravity ground modification of the slab model and the inner radius of the ground modification, the overall altitude of the work area and the height difference between the measuring points. Through the test of the theoretical model and the calculation of the measured data,it is found that the overall altitude of the working area and the height difference between the measuring points have a great impact on the gravity terrain correction. The spherical shell model should be used for calculation, and the suggested parameters are given, which can greatly improve the accuracy of gravity terrain correction.