Abstract: The principles and current development of the OBS (ocean bottom seismometer) are introduced in this paper, aiming at solving the oil and gas geological problems and revealing the deep stratigraphy and structures in the South Yellow Sea, which are not properly solved by multi-channel seismic surveys. The implementation of the OBS survey in the mentioned region is a success. The data of effective deep reflection wave and refraction wave have been obtained, which have laid a solid foundation for solving the deep geological problems.