In this paper, we used ‘qianku6’ of tatary buckwheat as experiment materials to determine the botany, the contents of nutritional and healthy components (total starch, amylose, amylopectin and flavonoids) with ‘3414’treatment of fertilizer. The results showed that there were obvious influence on the yield and quality of ‘qianku6’ with different rations of N, P and K. The plant height，main stem branch，and main stem node of ‘qianku6’ were highest when treated with N2P2K2, and the per grain number of ‘qianku6’was most when treated with N2P3K2.When treated with N2P2K1, the per grain weight and yield were highest. The thousand kernel weight were highest when treated with N2P1K1.When treated with N2P1K2, the total starch content was highest, while it was lowest when treated with N0P0K0. The amylose content was highest when treated with N0P0K0, while the amylosecontent was lowest when treated with N2P0K2. When treated with N1P2K1, the amylopectin content was highest. The flavonoids contents were highest when treated with N0P2K2; the amylopectin and the contents of flavonoids were lowest when treated with N0P0K0. It was concluded that N2K2P1 was best among 14 fertilizer treatments, and the results of fertilizer application and yield by using three-factor secondary fertilizer effect function and one-factor quadratic fertilizer effect function showed as follows: N, 75.62 kg·hm^-2; P, 24 kg·hm^-2; K, 17.21 kg·hm^-2; Y, 1539.95 kg·hm^-2.