Abstract: In order to study effects of drought stress in different growth stages on corn grain filling and yield，four treatments were set up，namely normal water，jointing stage drought，tasseling stage drought，and early filling stage drought，changes of dry matter accumulation，filling characteristics，starch related enzyme activity and yield of maize were studied.Results showed that drought significantly reduced dry matter accumulation of corn，and drought during tasseling stage and early filling stage significantly reduced dry matter accumulation and contribution rate after anthesis.Drought significantly reduced grain weight and filling rate，and drought during tasseling stage had a significant effect on dry matter accumulation.Drought significantly reduced activities of bound starch synthase（GBSS），soluble starch synthase（SSS），sucrose synthase（SS）and sucrose phosphate synthase（SPS）.Drought has an effect on yield，main effects of the corn were increasing length of bald tip and reducing number of rows.Yield of three periods of drought stress decreased by 15.15%，33.11%，and 22.00%，respectively.Therefore，jointing stage，tasseling stage and early stage of grain filling were more sensitive to water demand，has a greater impact on yield，especially in the corn tasseling period.Water supply should be ensured to ensure corn yield.