Effect of ammonium and nitrate ratios (0:100, 25:75, 50:50 and 75:25) on nutritional quality of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) with 3 cultivars were studied in hydroponics. The results indicated that, with the increasing of ammonium proportion in nutrient solution, the soluble sugar content in product organ of flowering Chinese cabbage increased gradually, but Vc content decreased gradually. Enhancement of ammonium by 25% or 50% in nutrient solution increased the soluble protein content in leaf significantly, while it increased gradually in stalk with the increasing of ammonium proportion. Free amino acids in product organ of flowering Chinese cabbage were improved significantly by enhancement of ammonium in nutrient solution. Integrated nutritional quality of flowering Chinese cabbage in 25% ammonium enhancement treatment was better than others under hydroponics condition.