Abstract: The simulation of water cycle based on the output of hydrological model driven by atmospheric data is a research hotspot in the field of atmosphere and hydrology. Using CMADS-driven SWAT model, the spatial and temporal distribution characteristics of key water cycle elements in Erhai basin during 2009-2016 were simulated. The results show that (1)CMADS data set can drive SWAT model well, and it has good applicability in Erhai basin, and can be used for water cycle simulation. (2) In terms of time, annual precipitation, actual evapotranspiration and annual water production in Erhai River Basin showed a first decreasing and then increasing trend, with increasing rates of 4.6 mm/year, 29.3 mm/year and 15 mm/year, respectively. The annual average precipitation, annual actual evapotranspiration and annual average water production were 792.8 mm, 565.5 mm and 286.1 mm, respectively. Spatially, the precipitation in the western part of Erhai Lake is the most abundant, followed by the eastern part and the lowest in the northern part. The spatial difference of actual evapotranspiration was relatively small, and the high value area mainly distributed around the Erhai Lake area. The spatial distribution of precipitation was quite different. The largest precipitation was in the western part of Erhai Lake, followed by the northern and eastern mountainous areas. (3) The moisture index showed an increasing trend, while the water production coefficient showed a decreasing trend. The average annual moisture index and water production coefficient were 0.61 and 0.43, respectively. The actual evapotranspiration was consistent with the precipitation trend, but contrary to the potential evapotranspiration trend, indicating that the water condition was the main factor limiting latent heat in Erhai Basin.