In order to find out the effects of different degrees of drought stress on the growth index and yield of semilate rice. In this experiment, a pot experiment was conducted with hybrid rice Tianyouhuazhan as material. Intermittent irrigation was used as control (CK) at tillering stage, booting stage, heading stage, and milk stage. Three water stress gradients of light drought (70% saturated moisture content), medium drought (60% saturated moisture content), and severe drought (50% saturated moisture content) were set to monitor soil moisture content. The plant height, number of tillers, leaf area, and chlorophyll content under different water gradients at different growth stages were measured, and the effects of different water stress treatments at different growth stages on rice growth index, yield, and its components were analyzed. The results showed that the inhibition of plant height at the jointing and booting stage was the most significant, the number of tillers and leaf area decreased most significantly at tillering stage, and the heading and flowering stage had the greatest effect on chlorophyll synthesis. As far as yield is concerned, the most sensitive stage is the heading and flowering stage. Different stress treatments reduced the effective panicle number, 1000-grain weight, and seed setting rate of rice, and reduced the yield by 27.57%, 44.23%, and 46.32% respectively compared with the normal control. The correlation analysis showed that the correlation degree of affecting yield from large to small was effective panicle, 1000-grain weight, and seed setting rate. Therefore, ensuring water supply at the heading and flowering stage can effectively improve 1000-grain weight, effective panicle, and seed setting rate, and increase rice yield and water use efficiency.