Abstract: The crop simulation model, CropSyst, was revised and validated in this paper. The potential productivity of main crops in the black soil zone of Songnen Plain was simulated by using CropSyst model. In addition, effective methods for simulation of crop productivity were explored. Study results show that the simulated values approach the measured values of some indexes for wheat and maize, such as yield, ET and aboveground biomass. The RMSE between simulated data and observed data ranged from 3.59% for aboveground biomass of wheat, to 8.02% for wheat yield. The modeling efficiency, EF were from 0.76 for maize ET, to 0.90 for wheat yield.