Recently,frequent drought and waterlogging due to climate change caused severe yield loss in spring wheat.The research about the effects of water stress after anthesis on starch formation had great importance for cultivation of spring wheat with stable production and high quality.In the present study,two spring wheat varieties Ningchun 4 and Ningchun 47 which were domain varieties in Ningxia province were selected as material. Four different soil moisture treatments including heavy drought,light drought,normal and water logging were performed by manipulating the post-anthesis soil moisture in pots.The results showed that post-anthesis drought significantly increased(P<0.05)the grain starch content during the earlier filling stage and significantly reduced(P<0.05)the amylose and amylopectin content during the mid and late filing stage so that significantly reduced(P<0.05)the total starch content during the late filing stage.The activities of four key enzymes associated with starch formation,AGPP(ADP-glucose pyrophosphorylase),UGPP(UDP-glucose pyrophosphorylase), SBE(starch branching Enzyme)and SSS(soluble starch synthase),varied with a single peak curve.Water stress depressed these four enzyme activities in spring wheat during the mid and late filling stage. The rate of amylose accumulation in the two spring wheat was significant positively correlated with the activity of SSS(P<0.01).