Abstract: The genetic correlation between the metabolism of C , N and the main quality of grain of rice was studied. The results indicate that increasing the soluble sugar content may contribute to a significant increase of total N content and ratio of sugar to nitrogen and a decrease of brown rice length, 1000-grain weight and amylose content simultaneously. Increasing the total N content may result in the increases of brown rice width and amylose content and the decreases of ratio of sugar to nitrogen, brown rice length and 1000-grain weight simultaneously. The increase of ratio of sugar to nitrogen may significantly lead to the decline of brown rice thickness, 1000-grain weight and amylose content . The results also indicate that seed, cytoplasmic and maternal genetic effects influence the genet ic correlation between paired traits simultaneously. The effects of different genetic systems vary among different trait pairs. Seed direct effects are the dominant genetic effect controlling the correlation between paired traits such as soluble sugar content and brown rice width, soluble sugar content and brown rice thickness, total N content and brown rice length, total N content and brown rice thickness, while maternal plant effects are the main effects controlli ng the correlation between paired traits such as soluble sugar content and 1000-grain weight, soluble sugar content and amylose content, total N content and brown rice width, total N content and ratio of length to width of brown rice, ratio of sugar to N and brown rice width,ratio of sugar to N and brown rice thickness.