Abstract: Under subsurface drip irrigation condition, the experiment was carried out, on the effect of lateral depth on the root and seedling growth of winter wheat in different growing stages. The results showed: the soil moisture distribution with the lateral depth of 20 cm and 40 cm,inhibited the seedling vegetative growth and spur the root to stretch in deeper soil in early stage，but promoted reproductive growth in later stage, and raised water use efficiency. The optimal lateral depth was 40 cm, disconsidering the hard soil layer under the tillage layer.