Abstract: Liquid phase co-sintering compatibility is one of the key technological problems in producing functionally graded materials (FGM), which is meaningful for studying the theoretical model. On the basis of the existing liquid phase sintering, LPM and solid phases co-sintering model, a liquid phase co-sintering model is established according to the basic parameters including the grain radius, the relative density and the liquid volume fraction. The methodologies and techniques described can be applied to simulate and predict the composition gradients and density during liquid phase co-sintering, which can be testified by YG cemented carbide experiment. The result shows that the density and Co content of the material in the both ends of the co-sintering sample interface presents gradient variation, which is in agreement with the variation of the calculation fitting. The established model can predict Co content of the YG8 cemented carbide and the gradient variation change rule of the density.