Five representative sweet cherry trees were selected from northern part of Hengduan Mountains for comparing physiological radiation,photosynthetic properties and fruit qualities of sweet cherry,especially analyzing light response of photosynthesis (P_n-PPFD) response curve and the correlation between fruit qualities and physiological radiation and photosynthetic parameters of sweet cherry.The results showed that:(1)The apparent quantum yield (α) was the highest,while light compensation point (LCP) the lowest in the substrate and inner part of canopy,which indicated sweet cherry leaves had a good ability of utilizing the low light.However,the light saturated point (LSP) was significantly higher in the top and outer part of canopy,which showed sweet cherry leaves had a good ability of utilizing the strong light.(2)The physiological radiation intensity and ratio of short wave light increased from the substrate to the top part and from the inner to the outer part of canopy.Thus,they indicated that sweet cherry reflected great capability of adapting to low or strong light.(3)The maximum photosynthetic rate (P_max),dark respiration rate (R_d),LCP and LSP were the highest in the top and outer part of canopy,enhancing leaves used efficiency to light intensity,increasing leaves ability of utilizing the strong light.The physiological radiation and short wave light intensity were strong,TSS,Vc and total sugar contents increased,but organic acid content reduced.