The dynamic-wave equation derived from the Manning equation was proposed to estimate run-off in BATS,which introduces surface slope and roughness to take into account the interaction between grid physical variables.The modified BATS was then coupled into the RegCM2.By using the T106 data in June to August 1998 as the boundary field,simulations of runoff were performed for eastern China.Simulations show that the runoff of the modified model reaches 80—500mm in the June to August,more closer to the observed values(50—500mm) than the value of the original(30—80mm) model.Therefore the modified BATS better manifests the large scale advection effect of runoff.From comparison of simulations by the modified model and original model at Wuhan station,it is found that the error of simulated average temperature by the modified model and the observed data reduces 0.66℃.The simulated precipitation by the modified model also agrees better with the observed than the original model.The paper also analysed the temperature,precipitation,soil water,evaporation,etc.