A study on analysising the difference of major flavonoid content and composition with HPLC method of rice grain catechin, myricetin, quercetin, kaempferol determination using high performance liquid chromatography method was conducted, which was to provide the theory basis for directional improvement of excellent high flavonoid germplasm resource. The main results are as follows: It was set up the HPLC method of rice grain catechin, myricetin, quercetin, kaempferol determination using high performance liquid chromatography method (HPLC). It was better than colorimetry. Major flavonoid in brown rice was composed of catechin and kaempferol , and not myricetin , quercetin. There was significant difference among the proportion and content. ( cultivars(lines) in japonica rice had more catechin；colored rice had more myricetin and kaempferol than uncolored rices. Brown rice contained more flavonoid than milled rice, while milled rice containing little or no flavonoid.