Waxy maize is widely cultivated under rainfed conditions and frequently suffers water shortage during the late growth stage.  In this study, a pot trial was conducted to examine the effects of post-silking drought on leaf photosynthesis and senescence and its influence on grain yield.  Two waxy maize hybrids, Suyunuo 5 (SYN5) and Yunuo 7 (YN7), were grown under the control and drought (soil moisture content was 70–80% and 50–60%, respectively) conditions after silking in 2016 and 2017.  The decrease in yield was 11.1 and 15.4% for YN7 and SYN5, respectively, owing to the decreased grain weight and number.  Post-silking dry matter accumulation was reduced by 27.2% in YN7 and 26.3% in SYN5.  The contribution rate of pre-silking photoassimilates transferred to grain yield was increased by 15.6% in YN7 and 10.2% in SYN5, respectively.  Post-silking drought increased the malondialdehyde content, but decreased the contents of water, soluble protein, chlorophyll, and carotenoid in the leaves.  The weakened activities of enzymes involved in photosynthesis (ribulose-1,5-bisphosphate carboxylase and phosphoenolpyruvate carboxylase) and antioxidant system (catalase, superoxide dismutase and peroxidase) reduced the photosynthetic rate (P_n) and accelerated leaf senescence.  The correlation results indicated that reduced P_n and catalase activity and increased malondialdehyde content under drought conditions induced the decrease of post-silking photoassimilates deposition, ultimately resulted in the grain yield loss.