Abstract: To reveal the effect of meteorological factors on water surface evaporation and determine main meteorological factors affecting water surface evaporation, the authors used correlation analysis and path analysis to analyze the relationship between water surface evaporation and other meteorological factors during 1979-2008 in Changwu. The results showed that: the variation coefficient of each meteorological factor was in suitable scope, which was in the following trend: temperature (CV=0.06) ＜water surface evaporation (CV=0.12) ＜precipitation (CV=0.24); there were correlations between water surface evaporation and other meteorological factors, and the correlation coefficients followed an order: temperature (r=0.930)＞precipitation (r=0.765); as to the direct effect of path analysis, the influence of temperature on water surface evaporation was more significant, while the influence of the precipitation was small, and showed a negative effect; from the perspective of the indirect effect of path analysis, precipitation had effect on evaporation which was mainly affected by the average temperature. The influence of precipitation on water surface evaporation was mainly affected by temperature which was determined as the main factor.