[Objective] Studying the distributed model of actual evapotranspiration in nationwide secondary river basins in order to provide the reliable basis for estimating basin actual evapotranspiration. [Methods] Based on the climatic and hydrological data during 1956 and 1979, the water balance method and the evapotranspiration complementary theory were used to propose the general model for improving the actual evapotranspiration of the river basin. [Results] (1) According to the actual evapotranspiration of many years, the spatial distribution had obvious zonal characteristics. (2) The trend line between the actual evapotranspiration and potential evapotranspiration had nearly overlapped over the humid areas and sub-humid areas basin. The distance between the trend lines of arid and semi-arid basins was relative large, but it still show a tendency to be closed. (3) The error simulated by hydrological and meteorological data of 77 secondary river basins was small than 10%. [Conclusion] Under different climatic conditions, the complementary link between actual and potential evapotranspiration clearly exists. The improved general model could be used to improve the estimating accuracy of actual evapotranspiration in the basin.