The apparent density mapping is of some help to the interpretation ofgravity data survey and, in covered areas, may serve as valuable reference datafor rock mapping. The anthor has designed an apparent density method forspace domain matrix calculation and, through tentative calculation by meansof the model, obtained an apparent density map with high resolution power.Its practical application in Tongling area shows that the apparent density mapreflects real condition of stratigraphic density distribution and thus can playa certain role in division of Iithologic cbaracters and delineation of intrusivebodies.