Abstract: Phreatic water is one of the available water sources for crop growth. In this paper,the long-term observation data of phreatic water evaporation and hydrometeorology at Wudaogou Experiment Station from October 1991 to May 2020 are used,the variation trend of phreatic water evaporation and water surface evaporation,surface temperature,air absolute humidity and air temperature at different buried depths（0～5 m）in winter wheat growth period are analyzed,the ratios of phreatic water evaporation to four meteorological factors at different depths of groundwater table in different growth stages of winter wheat are calculated（evaporation coefficient of phreatic water）,the functional relationship between evaporation coefficient of phreatic water and buried depth is constructed. The results show that based on four meteorological factors,the fitting relationship between phreatic water evaporation coefficient and buried depth is analyzed,the results show that all of them are positive:the exponential function of emergence tillering stage is the best,and binomial function of other growth stages is the best,the R2 is above 0.89,the fitting accuracy is high,it can be used to estimate the phreatic water evaporation of Winter Wheat in yellow fluvo aquic soil in Huaibei Area.