Abstract: The P-cable system of high-resolution 3-D seismic has been successfully applied to the researches of submarine gas hydrate, reservoir mapping and seafloor geohazards, especially to the internal structure and spatial distribution patterns of small targets such as seafloor gas chimneys and mud volcanoes. The P-cable system can also provide accurate high-resolution 3-D seismic data for ocean drilling site survey, especially for site selection and drilling time estimation. Comparing to the long streamer 3-D seismic survey commonly used by the industry, the P-cable system of high-resolution 3-D seismic is more flexible and easy to users. It is simple, fast and economic to marine geological and geophysical researches. The detailed description of 3-D structures of seafloor gas chimneys, which is usually done by deep diving, can be made by the P-cable system as well and thus the P-cable system of high-resolution 3-D seismic may be used as a supplement to deep diving and a strong seafloor mapping tool in the future. In this paper, we presented some real cases on the application of the system to the internal structures description of seafloor gas chimneys and mud volcanoes and their spatial distributions. We suggest that the P-cable system of high-resolution 3-D seismic be applied more often in the future to marine geophysical survey, specially to fine marine seismic investigation and associated scientific researches related to submarine gas chimneys, seafloor mud volcanoes and slumping slides in the areas of continental slope.