Water-saving irrigation is an important measure to improve water use efficiency and efficient rice production. The effects of four different irrigation water amounts on the yield, biomass, and water grain production efficiency of the widely planted rice variety Yuehesimiao were studied by pot experiment in Southern China. The results showed that with the decrease of irrigation water rate, the number of grains per panicle of rice decreased gradually, and the seed setting rate increased gradually, and the rice yield first increased and then decreased. Compared with CK (long-term flooding irrigation, 38.6 L/pot), T2 treatment (88.6% of long-term flooding irrigation water rate) increased rice yield by 14.55%, T4 treatment (36.8% of long-term flooding irrigation water rate) decreased rice yield by 45.28%, but there was no significant difference in T3 treatment (62.4% of long-term flooding irrigation water rate), indicating that reducing irrigation water consumption by 37.6% does not affect rice yield. Compared with CK, the biomass of T4 treatment significantly decreased by 50.84%, while was no significant difference in T2 and T3 treatments. Among the four treatments, the water grain production efficiency was the highest in T3 treatment, significantly increased by 62.38% compared to CK. In summary, under the conditions of this experiment, reducing irrigation water consumption by 37.6% does not result in a decrease in rice yield, and the water grain production efficiency is the highest.