Based on high-resolution 3D seismic data, the seabed pockmarks can be divided into isolated pockmarks and pockmark belts by their distribution in Rio Muni Basin, West Africa. Pockmark belts are distributed along meandering bands on seafloor. A single seabed pockmark can be in a range from 0.2 to 0.6 km2 in area and from 20 to 60m in depth. The seismic profiles across the isolated pockmarks or seabed pockmark belts illustrate U-shaped reflection characters of them an d the underlaying beds with increasing amplitudes and pulling-down seismic events, which implies the existence of gas chimneys under these seabed pockmarks, The seafloor along the strikes of the seabed pockmark belts is characterized by a ridge-by-swale topography. The distribution of the seabed pockmark belts are controlled by the palaeochannels so that the distribution of pockmark belts is coherent with that of alaeochannels in plane. The evolution of the seabed pockmark belts that are controlled by palaeochannels can be divided into four stages: overpressure build-up stage, overpressure release stage, pockmark sediments expulsion stage and pockmark formation stage. The genesis of pockmarks is relative to some geological conditions but all of pockmarks have been associated with fluids seepage or expulsion in sea floor strata.