Mathematical statistical techniques were used to analyse the relationship between Bouguer gravity anomalies and topographic elevations over an area of more than 3,000,000 km² in Southeast China. Through a discussion on this relationship, a method was put forward for separating gravity anomalies, by means of which the gravity anomalies related to elevations and residual gravity anomalies caused by geologic structures of the crust were separated and corresponding maps compiled.This furnishes information for inferring density structures of different tectonic units and their possible tectonic frameworks at depth.