Abstract: On the basis of the theoretical formula for gravity terrain correction, a coastal gravity terrain correction formula for correcting the influence of seawater gravity is established. After calculation, the slope angle of common coastal slope terrain increases from 1 ° to 10 °, and the maximum difference between the modified formula and the standard formula is 0.074×10⁻⁵ m/s² to 7.387×10⁻⁵ m/s², which directly affects the accuracy of gravity measurement anomalies. Taking the coastal zone of the East China Sea and the Beihuangcheng Island area in the Bohai Strait with relatively complex terrain as examples for forward calculation and analysis, the results show that using the established terrain correction formula for correction can effectively improve the accuracy of gravity measurement anomalies in the coastal zone.