The paper set up digital elevation watershed model and divided water system aimed at water collection area of Anningqiao hydrology station in Anning river basin,and simulated the daily runoff process of the watershed by means of two widely used rainfall-runoff software of MIKE11 and Xinanjiang hydrolical model.It chose DC and BIAS as two control indexes and. compared and analyzed the simulation results of RR model and Xinanjiang Model based on the theory of information entropy. Taking the day runoff as standard secquence and the computered day runoff as standard calculated residual, the paper normalized and calculated potential information measure and relative information entropy measure.The conclusions are that the maximum number of information entropy is practicable to determine the hydrological model's parameters and evaluate the simulating results.When carrying out comparative evaluation to difference models,the relative value of information entropy will also meet the principle of non-uniqueness of differential information theory.