Abstract: The submarine mud flow, a fluidized landslide mass developed from the unstable submarine slope, is easy to cause a serious damage to the offshore engineering facilities. At present, there are rarely researches to discuss the rheological properties of this mud flow, particularly lacking of its characteristic studies considering the low temperatures around the seafloor. For this purpose, the mud flow is prepared by using undisturbed soft clay samped from the South China Sea, and many rheological tests under different temperatures and water contents are conducted by the RST rheometer. Then, the Herschel-Bulkley model is introduced to analyze the rheological parameters, and the integrated rheological model for the submarine mud flow is proposed. Further, the rheological characteristics and mechanisms of the submarine mud flow are analyzed by the phase transformation, the Brownian motion and the interparticle interaction. The research results show that the shear stress and apparent viscosity of the mud flow under the low temperatures significantly increase as compared with those under the room temperature, and this change percentage will further rise with the increase of the shear strain rate, and the average value of the change is more than 35%. This study may provide a scientific basis for the numerical simulation of submarine mud flows and the prediction of landslide hazards.