Abstract: Marine geophysical exploration methods can be used for external detection of submarine pipelines. By starting with the in-situ states of the submarine pipelines, the existance characteristics, causes and treatment requirements of the buried, exposed and suspended states of the submarine pipelines are described and the functions and characteristics of various traditional marine geophysical exploration methods commonly used for the submarine pipeline detection in China at the present are introduced in the aspects of the basic principle and application process of instruments. The images of side scan sonar, sub-bottom profiler and multibeam bathymetry system obtained in the cross-sea water pipeline inspection project in Zhoushan are investigated. The results indicate that the methods of side scan sonar and multibeam system have better detection effects on the direction and shape of the exposed and suspended pipeline, the sub-bottom profiler can detect accurately the buried depth and surrounding strata of the submarine pipelines and the magnetometer is suitable for detecting the existance and position of the pipelines. Combined with the interference factors possibly encountered in the detection process and the principle limitations of the instrument itself, the capabilities and characteristics of the marine geophysical exploration methods are analyzed and compared, and the applicability and the advantages and disadvantages of these methods to the submarine pipelines with different states are summarized, in order to guarantee and improve the accuracy of the pipeline state discrimination. In addition, new marine geophysical exploration techniques are listed and the current situation and future development trend of submarine pipeline detection methods are discussed.