Abstract: The photosynthetic characteristics of leaves of Quercus pannosa at the different elevation spots of Gongga Mountain region were studied by using the Li-6 400 portable photosynthesis system. The results were as follows: (1) The diurnal variation of net photosynthetic rate (Pn) on sunny days in August were one smooth peak curve and had no midday depression. With the elevation increasing, the net photosynthetic rate and the transpiration rate and the water use efficiency decreased, but the conductance increased, which favored gas exchange of photosynthesis in the plants of high elevation; (2) There were obvious differences in the responses of Pn to photosynthetic active radiation at different elevation spots. The light compensate point(LCP) and the light saturated point(LSP) of leaves were 39.16～68.06/Lmol/(m2?s) and 1124.78～1754.88μmol/(m2?s) respectively. The apparent quantum efficiency was between 0.02812 and 0.03173. With the elevation increasing, the LCP, LSP and the maximum net photosynthetic rate of leaves increased; (3) The CO2 compensate point was between 68.47μmol/mol and 105.21μmol/mol. With the elevation increasing, the O2 compensate point decreased, which favored for adaptability of plants to the circumstance of low CO2 pressure in higher elevation regions. The CO2 saturated point was 700μmol/mol or so, and the carboxylation efficiency was between 0.035 and 0.038.