To explore the adaptability and response mechanism of plants to natural light environment from the perspective of physiology and ecology, we studied the photosynthetic and spectral characteristics of common tree species (Acer triflorum, Acer mandshuricum, Acer mono, and Pinus koraiensis) in Jilin Jiaohe broad-leaved Korean pine forest under three natural light environments (forest gap, forest edge, and understory). The results showed as follows:the light saturation point(LSP) and light compensation point(LCP) of saplings of the four tree species decreased with the decrease of ambient light intensity, and the LSP and LCP of saplings of all tree species were significantly lower than those of saplings in gap (P<0.05). Except Acer mandshuricum, The maximum net photosynthetic rate(P_nmax) of other tree species was significantly smaller than that of saplings in the gap(P<0.05). The apparent quantum yield(AQY) and dark respiration rate(R_d) of saplings of different tree species did not change significantly with the change of light environment, and there was little difference among different environments. The chlorophyll normalized index (Chl NDI) of sapling trees increased with the decrease of ambient light intensity except Acer mandshuricum. The photochemical reflectance index(PRI) value of understory trees was generally higher than that of trees under better light conditions, indicating that the chlorophyll content and photosynthetic rate of understory trees was higher than that of other light conditions. There were significant differences in the water index(WI)of leaves among different tree species in different light environments(P<0.05), and the WI of leaves decreased with the increase of environmental light intensity, showing that the water concentration of sapling leaves was the lowest under the gap environment.The structure-insensitive pigment index (SIPI) of three acer species at the forest edge was significantly lower than that of other light environments(P<0.05), indicating that the saplings under the forest edge were subjected to relatively little environmental stress.In the forest gap, Pinus koraiensis had the highest LCP, LSP, P_nmax, R_d and PRI, indicating that Pinus koraiensis had higher photosynthetic potential and was more adaptable to high-light growing environment. Among the three acer species, Acer mandshuricum had the highest Chl NDI and PRI values, indicating that it had good adaptability to the light environment in forest gap. These results indicated that Pinus koraiensis and Acer mandshuricum could renew well and occupy the canopy gradually in the gap environment.