Method for gravity-seismic joint inversion density interface distribution under spherical coordinate system

The invention provides a method for gravity-seismic joint inversion density interface distribution under a spherical coordinate system. The method comprises the steps of estimating an initial densityinterface depth, calculating a gravity anomaly matrix value after iteration of a corrected density interface depth, calculating a difference value [delta]hi between a known seismic constraint point and an inversion calculation point, carrying out the root-mean-square error analysis, and performing multi-iteration calculation and iteration end point judgment. The method has the beneficial effects that for regional large-scale density interface inversion research, the earth is approximated to be a sphere, a conventional prismoid is replaced with a sphere unit body, the problem that the earth curvature is ignored in large-scale research is solved, and the inversion result is closer to the real situation. Meanwhile, a depth weighting factor and seismic constraints are introduced in the inversion process, so that the i