Abstract: Characteristics of terramechanics of the surface soil on deep-sea bed are fundamental for the development of the miner of oceanic mineral resource-the polymetallic nodules on deep-sea floor. The physical properties of samples of the surface soil on deep-sea bed and two kinds of bentonite on land are lucubrated, and their properties are compared in details. Then the samples with similar physical properties to the surface soil on deep-sea is chosen to simulate the deep-sea soil. The paper analyzes the physical and mechanical parameters of both the surface soil on deep-sea bed and the simulating soil which is the bentonite-water mixture. With these parameters obtained, the simulating soil is made with high water rate, small inner friction angle, high liquid limit, high plastic exponent, big hole rate, low strength and low density. According to the terramechanics theory, experiments are carried out to characterize the pressure-sinkage relationship and the shear stress-shear displacement relationship. The experiment uses different flat plates at the vertical direction and track plates at the horizontal direction. The track plates have different teeth, pitch and height. Two expressions of the pressure-sinkage relationship are built based on Bekker theory and Reece theory respectively, as well as the shear stress-shear displacement relationship. Finally, the relationship between the driving force and slip rate of the surface soil is given, which can be used to analyze the polymetallic nodules miner in China.