Pot experiments were conducted in the early seasons and the later season of 2013.In each season,the hybrid rice cultivar Jiyou716 was planted under saturated soil moisture of 95%-100% (W100),80%-85% (W85) and 65%-70% (W70).The results showed that the root growth was seriously limited by soil moisture of W70 at the stage of elongation.The root dry weight significantly decreased.The effect of soil moisture on root diameter was the biggest at the stage of heading,but that on root surface area,volume and dry weight was small.The root of W70 appeared early aging at the stage of mature.The length,diameter,surface area,volume and dry weight of root was significantly reduced.The root with diameter between 0.0-1.5 mm was crucial to the root growth regulation under different soil moistures.The root with diameter between 0.0 -1.0 mm played decisive roles.There was no significant difference on root shoot ratio under different soil moistures and at the different stages.The ratio of shoot and root of W70 was lower than those of W100 and W85 at the stages of elongation and mature.The ratio of shoot and root of W70 was higher than that of W85 at the stage of heading.The dry weight of root and aboveground biomass,grain yield was significantly positively correlated in no-tillage rice.The root growth was inhibited by severe water stress at the stage of elongation.The root of W70 showed earlier senescence than that of W100 at the stage of mature.The aboveground biomass reduced,leading to the decrease of grain yield.Mild water stress did not make the root senescence slow down.The root with diameter between 0.5-1.0 mm was crucial to soil moisture on regulating the root growth under different soil moistures.