A phase field model is used to describe the microstructural development during the ceramic sintering. The evolution of the density is governed by Cahn-Hilliard equation, while the long-range order (lro) parameter fields by the time-dependent Ginzburg-Landau equation. In the simulation, green microstructures that consist of circular particles with different particle-size distributions and green densities have been produced by the stochastic growth model. The porosity of 25.6% was considered. The formation and growth of sintering neck, the seal, spheroidization as well as disappearance of pores and growth of grains are observed during simulation. The simulation results show grain boundary diffusion and surface diffusion are the dominate mechanism at the initial sintering stage. The predicted growth exponent of sintering neck and grain is consistent with the existing theoretical analysis.