Based on the microstructure evolution of cement hydration, using the relationship between the hydration rate and hydration degree, chemical shrinkage prediction model of cementitious materials are proposed. This model can simulate chemical shrinkage curve of cement-based material well. In the early period, increasing water-cement ratio can increase chemical shrinkage. While in the middle period, its influence on chemical shrinkage is negligible. Increasing temperature accelerates the hydration process significantly, therefore, increases the chemical shrinkage.