Abstract: On the basis of the development of laboratory equipment from which soil moisture can be measured automatically, the temporal variations of soil water content distribution during evaporation and post evaporation were analyzed,of which,the film hole ratios and irrigation quotas were diferent. Then after,through calculation and analysis of the cumulative evaporation, the three-factors empirical function of cumulative evaporation determined by evaporation time,open hole ratio and irrigation quota was developed. The function was based on the theoretical relation of Gardner's equation for bare soil evaporation,it can be considered as an extension of the Gardner's equation Moreover,the influences of open hole ratio and irrigation quotas on relative cumulative evaporation and cumulative evaporation per unit film hole area were analyzed,and the related estimation functions are also provided.