The performance of APSIM model in simulating lucerne(Medicago sativa)-wheat(Triticum aestivum)-millet(Oryza sativa)crop rotation system was assessed against the crop observations from Haiyuan region of Ningxia in Western China.The model parameters for characterizing plant growth and development of local cultivars were specified based on the crop observations in literatures or estimated using try-and-error methods.The model performance in simulating soil moisture and crop production of a lucerne-wheat-millet rotation system was assessed against the observations from the 6different crop rotation scenarios to validate the model parameterization.The simulations used local meteorological data and soil profile description at pilot site.The results showed that the modeled soil moisture matched well with the observed(R~2 value ranged between 0.52and 1,D value ranged between 0.92 and 0.97)and the modeled plant production simulated well with the observed(R~2 value ranged between 0.83 and 0.98,D value ranged between 0.94 and 0.99).This model parameterization and validation provides the confidence for using the model to optimize Lucerne-wheat-millet rotation system management and to assess climate change impacts on crop production in Haiyuan region of Ningxia.