Abstract: At present,there exist two types of method used to recover the bathymetry from altimeter data,i.e.the deterministic methods and the statistical method.In this paper,the principles of the two method are introduced first.Then on the basis of the theory of least-square collocation,a modified statistical model for recovering bathymetry from altimeter data is proposed.The new model is used to compute the ocean depth in the South China Sea from altimeter-derived gravity anomalies.And finally the predicted depths are compared to the ship-borne depth.