Abstract: In this experiment was studied the effect of N and K fertilizer on biochemical substances during flower stalk formation of the Chinese kale by six fertilizer treatments designated N1, K1, N1K2, N2K1, and N2K2. The results showed that soluble sugar, reducing sugar, protein and free amino acid accumulated in the stem, and the radio of soluble sugar to total protien (SS/TP) increased gradually before flower bud differentiation. When both carbohydrate and nitrogen compounds accumulated to a little peakk and SS/TP tatio achieved a certain value, flower bud was differentiation occurred. The carbohydrate content was highest, the protein content lowest and SS/TP ratio high, but flower bud differentiation was latest in K1 treatment when compared with other treatments.During flower stalk formation, the chlorophyll content of the leaves increased rapidly, free amino acids and sugars in the stem accumulated but the protein content wad reduced. However, a chift occurred in which the chlorophyll and the sugar content decreased, but the protein content increased again at around flower bud production. The soluble sugar content was highest, the protein content in the stem lowest, so that the SS/TP ratio was high, but the flower stalk development was least in K1 treatment in comparison to other treatments.The DNA content in stem apice showed no marked change, but the RNA content increased gradually and reached a little peak before flower bud differentiation. Durinng flower stalk formation, the RNA content increased rapidly whereas the DNA content slowly. These changes did not significantly differ among all treatment.