Abstract: Abstract: When the offshore gravity data is processed, the impact of coastal mountains on ship gravity data cannot be ignored. This paper deals with the methodology to reduce the influence of offshore mountain masses on ship measured gravity data, and the point element method is introduced to calculate the value of the influence. Then a method is given to eliminate the influence. Taking the working area off the Laoshan mountains as an example, by calculating the influence value of Laoshan, the distance between the measured point and the mountain is inversely proportional to the influence value, and the maximum is 0.12 mGal. When the distance exceeds 20 km, the influence value is neglected. Through the above method, more accurate ocean gravity data can be obtained for better geological interpretation.