Microstructures play an important role in sintering. Hlowever, most existing sintering theories are macroscopic and do not consider the topological constraints in a microstructure. To fully take into account the microstructural effect, Anderson et al. [l] developed a Monte Carlo statistical mechanics model to study the grain growth behavior of a fully dense system. lHere we developed a generalized model which allows both densification and grain growth to occur. The densification occurs through the diffusion of matter and is incorporated in the Monte Carlo procedure. Thus we can monitor both the microstructural evolution and the densification at the same time during heat treatment. To our knowledge, this is the first statistical mechanics model constructed for sintering. As a quantitative example, the sintering behavior of an isolated pore of various sizes and shapes at different grain growth rates is studied.