To investigate the effects of oxygen-phosphorus(P) management on root activity, yield of rice and their relationships, we adopted two irrigation regimes and three P management on the hybrid rice C Liangyou 608. The experimental groups were the two water regimes, non-oxygation (oxygenirrigation NI), oxygation(OI), three P managements, P1(0.18 g/kg), P2(0.36 g/kg), P3(0.54 g/kg), and the control without P application(P0). The results showed that, P fertilizer operation had a significant difference on 1 000-grain weight and root activity, and theoretical yield was significantly positive to root activity at tilling stage with P application. The oxygation had a significant difference on theoretical yield, effective grain number, and grain number per panicle. When the P application was less than 0.36 g/kg and oxygation, theoretical yield and effective grain number increased by 1.04%-23.69% and 21.29%-50.03%, respectively, grain number per panicle decreased by 11.49%-25.61%. The theoretical yield, offective grain number and 100-grain weight were maximum without P application but oxygation. The interaction between oxygation and P had a significant interaction difference on theoretical yield and 1 000-grain weight, 1 000-grain weight was significantly negative to root activity at seedling and tilling stage. Phosphorus application or oxygation can increase the yield by affecting the root activity at growth stage, compared with the treatment of phosphorus application or oxygation, the interaction of oxygen and phosphorus had the tendency to reduce the yield.