Abstract The WGM2012 gravity anomaly data is used to calculate the Moho depth in Papua New Guinea under the spherical coordinate system of the spatial domain. By separating the regional gravity field, the gravity anomaly caused by the fluctuation of Moho surface is obtained. The average deviation between the calculated results and the Moho depth results of the CRUST1.0 model is 0.44 km, and the standard deviation is 3.17 km. The results show that the depth distribution of Moho in Papua New Guinea has obvious regionalized structural features and is related to the subduction and collision of the area.