In order to explore the suitable light conditions of Apostichopus japonicus in indoor culture, 1680 juvenile sea cucumber (weight 0.185±0.014 g) were placed in three irradiance (1 000 mW/m2, 2 500 mW/m2, 4 000 mW/m2) in the environment of red (R)、full spectrum (W) and dark (D) for 35 days. The results showed that different spectra and irradiance could significantly affect the growth and physiological function of juvenile sea cucumber. The body weight of the red light 4 000 mW/m2 group was significantly higher than that of the full spectrum 4000 mW/m2 group (P<0.05). The body length of the red light 1 000 mW/m2 group was significantly higher than that of the full spectrum 4000 mW/m2 group(P<0.05). The specific body weight growth rate of the red light 1000 mW/m2 group was significantly higher than that of the full spectrum 4000 mW/m2 group (P<0.05). The survival rate of the red light 4000 mW/m2 group was significantly higher than that of the full spectrum 4000 mW/m2 group(P<0.05). For enzyme activity, amylase (AMS) activity was the highest in the red light 4000 mW/m2 group and lipase (LPS) activity in the red light 2500 mW/m2 group. The activities of acid phosphatase (ACP) and alkaline phosphatase (AKP) in the red light 4000 mW/m2 group were significantly higher than those in the red light 1000 mW/m2 group (P<0.05). The catalase (CAT) activity was the highest in the full spectrum 2500 mW/m2 group. The activity of superoxide dismutase (SOD) was the highest in the red light 4000 mW/m2 group, which was significantly higher than that in the full spectrum 1000 mW/m2 group(P<0.05). In summary, it is recommended to use red light to cultivate juvenile ginseng in an indoor culture environment and control the irradiance at 1000-4000 mW/m2. In this study, the effects of three irradiance degrees on the juvenile ginseng were studied, and the results showed that the growth performance of the juvenile ginseng with red light of 1000-4000 mW/m2 was better. In order to accurately and optimally determine the most appropriate irradiance, a fine irradiance gradient was recommended to further evaluate the effect of irradiance on the young radiance.