Photosynthetic characteristics and parameters of chlorophyll fluorescence of soybean and pepper were examined in an agroforestry system. The results indicated that photosynthetic active radiation (PAR) was reduced significantly from full daylight at 1m from the tree (Prunus salicina) row. The diurnal variations of photosynthetic rate (Pn), stomata conductance (Gs) and transpiration rate (Tr) of soybean and pepper were similar to photosynthetic active radiation, and they were lower in the agroforestry system compared to full daylight. The PAR was highly correlated with Pn, Gs and Tr of the both crops. The content of total chlorophyll and apparent quantum yield (Ф) of both crops increased and light compensation point (LCP) and light saturation point (LSP) decreased with increasing degree of shade. Meanwhile the Fv / Fm, ФPSⅡ and qP were significantly higher than those under full daylight in treatments of both crops, but qN P decreased with increasing degree of shade, which indicated that soybean and pepper had strong adaptability to low irradiance.