In order to explore the effects of 4 light quality treatments on the photosynthetic parameters of Chinese fir seedlings, one-year-old superior clone 020 cutting seedlings were used as experimental materials, 4 light qualities, 8 gradient light intensities were set; through the indoor light quality cultivation, the photosynthetic rate (P_n), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), transpiration rate (T_r), water use efficiency (C_WUE) and other parameters of Chinese fir seedlings were studied, and fitting analysis on light-intensity data was performed to establish a fitting model. The results showed that: under low light conditions, blue light and red: blue (1:1) had significant effects on photosynthetic parameters of Chinese fir seedlings, while under strong light, red light had a significant effect. The photosynthetic rate (P_n), stomatal conductance (G_s) and water use efficiency (C_WUE) of Chinese fir seedlings under red light treatment were different from other light quality treatments, but the intercellular CO₂ concentration (C_i) and transpiration rate (T_r) were slightly lower than those under the blue light, and the difference among the three light quality conditions: blue light, red light and red: blue (1:1) was not significant. In terms of the fit between light intensity and light quality, stomatal conductance (G_s), intercellular CO₂ concentration (C_i), and transpiration rate (T_r) fitted better. Therefore, to a certain extent, red: blue (1:1) light can promote the photosynthetic parameters of Chinese fir.