Abstract: This paper conducted some measurements,with Li-6400 portable photosynthetic apparatus,on six typical tree species,namely,Viminea wall,Rhododendron fortunei,Schima superba, Cyclobalanopsis stewardiana, Ilex wenchowensis, Sycopsis and so on within the forest ecosystem of Fengyang Mountain. Their photosynthesis and transpiration characteristics in diurnal patterns at canopy level were determind. Furthermore, the influence degree of physiological and ecological factors on net photosynthetic rate(P_n)and transpiration rate(T_r)were analysed and compared by using grey correlation method.Results showed that only Ilex wenchowensis presented double peak in the daily variation of P_n, Rh. fortunei had the strongest ability to use weak light. The main factors influencing T_r were stomatal conductance(G_s)and leaf vapor pressure deficit(D_vp). The daily average transpiration rate of Rh. fortunei and S. superba were lower while the daily average net photosynthetic rates of those two tree species were higher,so that their ability to accumulate carbon assimilation was more stronger; The main factors affecting the plant P_n were stomatal conductance(G_s)and water use efficiency(E_WU), meanwhile, the main factors affecting the plant T_r were G_s and photosynthetic active radiation(R_PA). According to the grey correlation analysis, Rh. fortunei possesses superior adaption and resistence to the habitat,S. sinensis has weak ability to adapt to the habitat due to the restriction by illumination, stomates and moisture.