Based on the ground-based observation data from 147 meteorological stations in nearly 50 years over the Yangtze River basin,applying climatology computational method for estimating global solar radiation,variation relationship between global solar radiation and 20 cm pan evaporation was contrasted and analyzed from 1960 to 2007.The main results are as follows:significant negative trend of global solar radiation and pan evaporation were detected in the upper,middle and lower reaches.Significant positive correlation existed between the global solar radiation and 20 cm pan evaporation,and the pan evaporation varies accordingly with the fluctuation of global solar radiation.The correlation coefficient between global solar radiation and pan evaporation in lower reach is higher than that in upper-middle reaches.In term of the seasonal variation,the research result indicates the same trend as the annual variation,and the variation of both global solar radiation and pan evaporation showed significant negative trend in four seasons of the whole basin,especially in spring,summer and autumn,which contributes most to the decrease of pan evaporation in a year.Therefore,the significant negative trends in global solar radiation over the basin can be considered one reason that causes the decrease in pan evaporation.