Abstract: 【Objective】 The effect of water control on rice during grain-filling stage was studied in this paper，providing a theoretical support for water-saving rice cultivation in arid areas. 【Methods】 At rice filling stage，three lower limits of irrigation control were set：90% θs （field water-holding capacity），80%θs and 70% θs （marked as W₁，W₂ and W₃，respectively），and conventional flood irrigation was set as control （marked as CK）. The photosynthetic characteristics，protective enzyme activities，osmotic adjustment substances，root activity，yield and water use efficiency of rice under different water conditions were compared. 【Results】 Water controlwould weaken photosynthesis of rice in the filling stage. The results showed that the P_n （net photosynthetic rate），T_r（intercellular carbon dioxide concentration），G_s（stomatal conductance） and C_i（Intercellular carbon dioxide concentration） decreased by 15.12%-72.38%，25.32%-67.59%，5.93%-24.34% and 29.62%-62.61%，respectively. Water control can enhance the enzyme activity of rice antioxidant system in the filling stage. SOD，CAT and POD of W₃ were the highest，which were 77.78%，24.64% and 14.24% higher than those of CK. In the filling stage，the lower the water control limit，the higher the soluble sugar content and proline content，the lower the soluble protein content. The soluble sugar content of W₃ was 1.35-2.32 times of that of other treatments，and the soluble protein content of CK was 6.72%~25.24% higher than that of the three water control treatments. The highest yield of CK was 8 222.12 kg/hm²，which was 16.37%~59.96% higher than that of W₁，W₂ and W₃. Compared with CK，water consumption for W₁，W₂ and W₃ decreased by 56.06%~61.66%，and water use efficiency increased by 38.65%~48.79%. 【Conclusion】 Water control during grain filling period under mulch drip irrigation has a negative effect on physiological and biochemical characteristics and rice quality，and it is not suitable to control water. During the grain filling period，the upper and lower limits of water control were set to 5 cm and 10 cm，respectively，to ensure high quality and high yield of rice.