Abstract: Marine geological survey data, which was collected from a wind farm, indicates that there is a great quantity of submarine shallow gas in the South Yellow Sea. On seismic profiles, the shallow gas is characterized by various features, such as the sudden interrupt of continuous reflection, random reflection, gas blocks, lower resolution and quick attenuation of high frequency components. No fault has been found in the research area, and thus the submarine shallow gas is well preserved. Data suggests that the gas is a kind of methane biogenetic gas. The depth of the diffuse gas is about 5 m, while the top of high pressure zone is about 272 m. Therefore, a 75 m drilling hole is beyond the high pressure zone. The submarine shallow gas has no risk and impact to submarine engineering programs in the region.