Abstract: Winter wheat is a main summer food crop in North China.Drought is one of the main agrometeorological disasters,which seriously impacts the growth and development and yield formation of winter wheat in North China.Studying the impact mechanism of soil water change on winter wheat is favorable to understand radically the responsible rules and physiological reaction of winter soil drought. That has a very important sense to drought defense and winter wheat yield increase.This paper,through the experiment of pot sowing by soil water controlling,systemically studied the relationships between physiological and ecological parameters of winter wheat leaf and soil moisture.The results showed that the soil drought stress increased stomatal densities,and the response on different sides of leaves to soil moisture was remarkably then different.The stomatal densities on the upper epidermis were greater than those on the under epidermis.The stomatal opening became smaller as soil moisture decreased.With soil moisture changing,the physiological process of winter wheat was also changed.The stomatal resistance was increased as the soil moisture decreased.It shows a parabolic function in the form Y=86.7264+7.9841X-0.7053 X2 The stomatal conductance was exponentially related with soil moisture,and it was exponentially decreased with the decreasing of soil water content:q=0.00017025exp (0.43705X) The transpiration rate was exponentially decreased with the decreasing of soil moisture:Rn =0.0712215exp(0.163909X) The relationships between transpiration rate and stomatal resistance were in exponential functions under any soil moisture,the difference is only the slope changed.The proline content in leaf was linearly increased as the soil moisture decreased:X=86.5538-0.27685p The increment of proline content in leaf is likely related to enhancing the function of anti-drought.Further more,the paper also studied the relationship between soil drought and chloroplast ultrastructure.The results showed that the chloroplast ultrastructure of winter wheat leaf was changed under soil drought,and thereby,it influenced plant photosynthetic function.