Based upon an approximate formula of three-dimensional gravity anomalies and by using the successive approaching method, an inversion technique for the computation of density data in regional gravity survey has been obtained. The technique was applied to process gravity data from_the middlelower reaches of the Yantze River, and a map of Moho isobaths of the area was constructed.Acomprison of calculated results with seismic sounding data shows a fairly good agreement. Acomputer program for the technique is being developed for the interpretation of regional gravity data.