Abstract: To study the potential of high-yield winter wheat in dry land, the effects of supplementary irrigation on carbon metabolism in late growth stage of high-yield winter wheat in dry land were studied. The results showed that supplementary irrigation obviously regulated the carbon metabolism index of flag leaf in dry land. With the increase of supplementary irrigation time, the changes of soluble sugar and sucrose content in leaf and stem showed a single peak curve, which rose first and then declined. Because of excessive water, soluble sugar content in grain of W4 was relatively low in the early filling stage. Sugar in nutritive organs of W2 was stably supplied at the filling stage, which provided enough synthesis substrate for the accumulation of grain starch. The SPS and SS activity in flag leaves were the highest in W2. It showed that by a certain agronomic measures, dry land could have higher capability of water storage and moisture conservation, thus to reach the goal of“the dry land which are not drought”to a certain degree.