Abstract In frequency domain，the gravity isostasy on Shatsky Rise was studied by 3D admittance analysis of gravity anomalies and bathymetry，referenced to Airy and Flexural isostatic models respectively.According to Airy model，it indicates that the mean crust thickness of Shatsky Rise is about 15 km，and the depth of Moho discontinuity beneath Tamu massif is about 26 km，which is consistent with the result that given by seismic studies.According to flexural isostatic model，it shows that the effective elastic thickness of lithosphere around Shatsky Rise is 1~5 km.That means the rise is an “On Ridge” structure.Taking into account both the topography and material loading at the bottom of the crust，the result shows that the amplitude of material loading at the bottom of the crust is about 50 ％ of the topography，and the average loading depth is 20 km.Shatsky Rise may be supported by the buoyancy of bottom loading mainly.
