Abstract:According to the relationship between the spherical cap function and the point mass model,a model was proposed based on multilayer point mass model structure coefficient of spherical cap harmonic method.Taking a region (32°N34°N,102°E104°E)as the calculating area,the Gravity anomaly was calculated using the three layers spherical cap harmonic coefficient which constructed by EGM2008 model and the Gravity measured observations.Analysis of fitting precision of gravitational field under different spherical cap harmonic order indicates that the average error between the spherical cap harmonic model and the measured observations is less than 0.5×10-5 ms-2,and internal consistency accuracy of the model is 4.56×10-5 ms-2 when Spherical cap half angle is 0.71°.