Abstract: Trinidad Basin, which is located in the northern part of Venezuela in South America and the southern margin of the Caribbean Sea has a good prospect for oil and gas resources. The formers have studied the tectonic evolution, sedimentary characteristics of the basin, the work was mainly focused on the southeastern basin, there is lack of research on the characteristics of the structure of the entire basin. In order to study systematically the distribution of faults and basement characteristics of the basin, predict the prospective areas of hydrocarbon, and provide a basis for further hydrocarbon exploration and development in the basin. This paper uses ship log gravity data and satellite gravity data provided by GETECH to analyze and study the characteristics of the gravity field of the basin, infer the fault structure system of the basin. With the constraints of the three existing seismic profiles, the three gravity profiles with the same position as the above seismic profiles were fitted, the basement depth of the basin is calculated combined with correlation analysis and Parker, the structural units and favorable hydrocarbon exploration areas of the basin are predicted. The results show that the structure of Trinidad basin is complex, there are mainly two groups of faults in NE direction and NW direction, the NE-oriented main faults control the scope of the basin and the development of stratum in the basin. The basement of the basin is undulating and can be divided into six structural units: the eastern subbasin, the northern subbasin, the central uplift belt, the central nappe belt, the western subbasin and the western uplift. The eastern sub-basin, the north sub-basin and the western sub-basin are favorable areas for hydrocarbon exploration.