Abstract: Pockmark is a form of depression geomorphology caused by quick eruption or slow aeepage of formation fluid towards the seafloor. A profound research on its morphology and formation mechanism is of great significance. Based on the high-resolution multibeam, sidescan sonar, sub-bottom profile and multichannel seismic data from the waters of Qingbang Island, Zhoushan Archipelago, seabed pockmarks and the microtopography inside them are discussed. The results indicate that three large crescentiform, elongated pockmarks were all reformed by the NE-SW bottom current. It shows that the western sidewall is higher and steeper than the eastern. The microtopography inside the pockmarks are composed of unit pockmark, or composite pockmark and chain pockmark. Characteristic reflection of shallow gas such as acoustic turbidity exists in the stratum. Analysis on hydrocarbon isotope shows that the gas is biogenic. Induced by typhoon activity, three large pockmarks were also formed by the quick eruption of methane gas in the Quaternary stratum, while microtopography were formed by the subsequent slow escape of small scale gas.