Owing to interferences of several factors, the deep seismic data obtained from northeastern South China Sea basin are poor in quality, low in signaltonoise ratio and weak in effective wave energy. In addition, the characteristics of reflection waves of the mediumdeep layer are not clear. In view of such a situation, the method of comprehensive interpretation that applies gravimetric and magnetic data in combination with seismic data is adopted in this paper. By analyzing the features of peripheral rocks in the study area and further processing and analyzing the gravimetric and magnetic data in combination with the stratigraphic analysis, the authors found the distribution of Mesozoic strata, thus providing a scientific basis for oil and gas exploration.