Abstract: The purpose of this paper is to investigate and predict the deformation behavior during the sintering of metal parts for binder jet additive manufacturing (BJAM). A viscoplastic constitutive model is developed. The model is based on continuum media mechanics and Newtonian viscosity, and integrates the effects of grain growth factor and frictional contact between the part and substrate under gravity on sintering deformation. The parameters in the present constitutive model depend on grain size, relative density and temperature. Write umat subroutine in Abaqus using this constitutive model to simulate the sintering behavior, and the widely used 316L powder was selected for experiments. The calculated values of shrinkage deformation, etc. were compared with the experimental data, and the results showed that the constitutive model has good prediction.