Appropriate phosphate fertilizer is very important to increase the yield and quality of rice and enhance resource utilization efficiency. In this study，we investigated the influence of different phosphorus applications on the grain yield，rice quality and root growth，and explored the relationship between root growth and rice quality，in order to provide a theoretical basis for high-yield，high-quality and efficient cultivation of rice. A pot experiment was conducted using the weak tolerance to low phosphate variety of Lianjing 7 and strong tolerance to low phosphate variety of Yongyou 2640. Four phosphorus fertilizer rates were set up，namely 0，60，120 and 180 kg·hm-2(indicated as P0，P60，P120，P180，respectively). The rice root length and root physiological activity，yield and quality indexes were measured at three period of mid-tillering，heading and maturity stage，and grain quality of rice was measured，respectively，so as to analyze the effect of different treatments on grain yield，rice quality and root growth. The results indicated that grain yield，milling quality，appearance quality，cooking and nutritional quality，root length，root oxidation activity and acid phosphatase activity all showed a trend of first increasing and then decreasing，with the above indices of Lianjing 7 reaching the highest at P120 treatment，while the indices of Yongyou 2640 were the highest at P60 treatment. Compared with no phosphorus application，the root length，root oxidation activity and acid phosphatase activity of Lianjing 7 increased by 51.1%，21.3% and 14.6% respectively at heading stage under P120 treatment，the root length，root oxidation activity and root acid phosphatase activity of Yongyou 2640 increased by 66.6%，32.7% and 17.7% respectively at heading stage under P60 treatment. Under the different genotypes，the grain yield，milling quality，cooking and nutritional quality，root length，root oxidation activity and acid phosphatase activity of Yongyou 2640 were higher than those of Lianjing 7，and the chalky area，chalky grain rate and chalkiness degree of Yongyou 2640 were lower than those of Lianjing 7. According to the correlation analysis，root length，root oxidation activity，root acid phosphatase activity were significantly positively correlated with milling quality，significantly negatively correlated with appearance quality；and the root length was significantly highly positively correlated with gel consistency. Yongyou 2640 with P60 treatment can more improve the root morphology and physiology，promote the absorption and utilization of water and nutrients，increase the filled grain rate and grain weight，and thus promote high yield and high quality of rice.