Abstract: In order to meet the requirements of 1:250 000 regional marine geological survey and solve essential geological problems of the onshore-offshore transition zone, based on the compilation of 1:250 000 magnetic and gravity anomaly map, the authors analyzed the magnetic and gravity anomaly characteristics of the main faults in Rizhao-Lianyungang area. According to regional geological materials, the authors discussed the magnetic and gravity anomaly characteristics and geological significances of the main faults, such as Yishui segment of Tanlu fault, Sangxu-Lianyungang fault and Donghai-Ganyu fault. The results show that Changyi-Dadian fault is the main fault of Yishui segment of Tanlu fault. And as the southern boundary of Sulu orogenic belt, Sangxu-Lianyungang fault controls the distribution of basement, strata and magmatic rocks. In addition, Donghai-Ganyu fault cuts Sulu orogenic belt into southern and northern segments. These new geological recognitions have provided important references for the geological research in Rizhao-Lianyungang area.