Based on data of magnetic fields, this paper makes an tentative investigation on such aspects of Lop Lake and surrounding areas as characteristics of magne tic fields, properties of basement, and geologic structure at depth, and points out that the central latitudinal rising anomalous belt of Tarim Basin extending to the Lop Lake area has the same basement made up of Lower Proterozoic onArcheozoic strong-magnetic crystalline complexes, thus considering that the Lop Lake area is a part of the Tarim Platform. It is unequivocally indicated in this paper that the eastern boundary of the Tarim Platform is at somewhere near 90°30', without further eastward extension.The paper also demonstrates that the Kuruktag uplift is consistent with So uth Tianshan Mountains but quite different from the Tarim Platform in deep-seated geological structure. During Proterozoic or Lower Paleozoic, it was in a platform-facies sedimentary environment; however, the Hercynian tectonic mo vement caused it to be involved in the movement of Tianshan tectonic belt. Ne vertheless, its ultimate assignment remains to be solved through further investi gation. In this paper, the authors describe the fust delineation of the Lop Lake depression by aeromagnetic survey, and evaluate oil-gas geology, structural con dition and basic prospect of the Lop Lake area in camparison with the neigh bouring areas.