Using Li-6400 portable photosynthesis measurement system, the photosynthetic capacity of Huangguogan seedlings treated with sodium nitrate and ammonium acetate in 11 different ratios was measured in different seasons. The results showed that 1) the net photosynthetic rate of all treatments was the strongest in summer, the worst in winter, and stronger in autumn than in spring; and the contents of chlorophyll a, chlorophyll b and total chlorophyll were the highest in summer, the lowest in winter, and higher in autumn than in spring; 2) when the ratio of sodium nitrate and ammonium acetate was 8∶2, the net photosynthetic rate, transpiration rate, water use efficiency, stomatal conductance, chlorophyll a, chlorophyll b and total chlorophyll content of Huangguogan seedlings were higher than those of the other treatments, and the above parameters in the treatment of sodium nitrate or ammonium acetate was low. Comprehensive comparative analysis showed that when the ratio of sodium nitrate and ammonium acetate was 8∶2, the photosynthetic capacity of Huangguogan seedlings was the best.