Abstract: Using flowering Chinese cabbage ’YoulCutai’as material,the experiment was conducted to investigate the effects of different boron levels on the photosynthesis and quality of plants in hydroponics. The results showed that the appropriate concentrations of boron could improve the photosynthetic characteristics, increase the content of carbohydrates and soluble proteins, and decrease the nitrite content, and thus improve the quality and the edible safety. Within the concentrations, treatment of 0.4 mg/L boron significantly improved the contents of chlorophyll, sucrose, fructose, starch, soluble protein, free amino acid, and decreased the nitrite content of flowering Chinese cabbage, and thus improve comprehensive quality.