Abstract: About 250 km gravity-magnetic profile data were obtained in Chaoshan depression in the Northern part of southern China sea for the first time. The crust structure of Chaoshan depression was studied, the distributions and attributes of the volcanic rock was analyzed qualitative. Based on Euler deconvolution, the position and depth of the source of gravity fields was estimated, the northern margin faults of continental slope and Dongsha faults was divided. According to dissecting depth of the zone of faults, the two zones of faults with upwelling of magma were transcrust (crust-upper mantle zone of faults). The depth of Moho-surface was calculated by Parker-Oldenburg inversion. Using moving average of logarithmic energy and men-computer mutual system, the depth of magnetic basement was inversed.The results shown that the depth of Moho-surface in Chaoshan depression was uplifted gradually from northwest to southeast direction, the beginning poing was about 25km deep, and the end point was 14 km deep.The depth of magnetic basement was deepen gradually from the start station 3.6 km of the measuring line in northwest direction to the end station 8.9 km of the measuring line in the southeast direction.

Key words: the south China sea, Chaoshan depression, gravity and magnetic anomalies, crustal structure