Abstract: An investigation during 2006-2009 on the submarine pipeline route in a gasfield showed that varying degrees scouring on the pipeline was found. This kind of scouring seriously threatened the safety of pipeline. The main reason for the scouring was the horseshoe vortex and trailing vortex generated under the action of high-speed flow field around the submarine pipeline. In the porous soil environment, this kind of vortex formed seepage flow easily, and "piping" afterwards. Experiments displayed that the scouring mechanism between cohesive seabed and sandy seabed was different. And the factors influencing local scouring on cohesive seabed were summarized. It was also found in experiments that the "piping" was easier to happen in the soil deposited soon with less intensity, which was different in the cohesive soil deposited for a long time. Furthermore, considering the angle between water flow and pipeline, an approximate calculation formula was proposed for scouring pit expanding along pipeline on the cohesive seabed. Four kinds of submarine pipeline rehabilitation technologies such as supporting pipeline, filling sandbags, covering by bionic structure and re-excavation were introduced briefly.