Photosynthetic rates and leaf bleaching were measured under light of far-red, red, orange, green, blue and white in order to clarify the effect of light qualities on photosynthesis in Panax species, P. ginseng and P. quinquefolium. Photosynthetic rate of P. ginseng and P. quinquifolium showed higher in the order under the light of red > orange > blue > white > green. Degree of leaf bleaching in P. quinquifolium showed severer in the order under the light of far-red > red > white > blue > orange > green. These suggest that shading material with blue or orange color is good for ginseng growth. As for the effect of temperature, the photosynthesis was increased with increasing temperature untill $25^{circ}C$ and thereafter decreased. Therefore, it was clarified that the optimum temperature for photosynthesis of P. ginseng and P. quinquefolium was $25^{circ}C$. And the dark respiration rate of ginseng leaf also increased with increasing air temperature. Especially, the dark respiration rate increased by $80\%$ for P. ginseng and by $73\%$ for P.quinquefolium at above $30^{circ}C$ as compared with $25^{circ}C$. In general, the photosynthesis rate was higher in P. quinquifolium than in P. ginseng and ranged from 3.54 to 4.04 mg $(CO_2{cdot}dm^{-2}{cdot}hr^{-1})$ for P. quinquefolium and from 2.08 to 2.59 mg$(CO_2{cdot}dm^{-2}{cdot}hr^{-1})$ for P. ginseng.