Abstract: The simulation of shear deformation process of deep-sea sediments is an important basis for the design of deep-sea mining systems. Firstly, according to the geotechnical mechanical features and the shear deformation characteristics of the process of deep-sea sediments, a shear damage model for deep-sea sediments is established by analyzing the force upon the deep-sea sediments on microscopic scale. Secondly, based on the comprehensive analysis of the method for measuring microcosmic element strength of the deep-sea sediments, a new statistical damage evolvement model is developed by introducing the statistical damage theory and supposing the strength of micro-units of which deep-sea sediments obey Weibull distribution. Then, by using the above shear damage model and statistical damage evolvement model, a shear deformation statistical damage constitutive model for the simulation of shear deformation process of deep-sea sediments is proposed, which can well reflect the characteristics of strain-softening of deep-sea sediments and describe the impact on shear deformation process of deep-sea sediments by normal stress in shear plane. Finally, it is indicated by the comparison among the theoretical, experimental and existing similar model curves that the proposed model is reasonable and feasible.