To study the photosynthetic characteristics of Yuquandongzao during crisp ripe period, Li–6400XT portable photosynthesis system was used to measure the diurnal change of net photosynthetic rate (Pn) and gas exchange parameters of single leaf on vegetative and fruit branches in different weather in open areas, different position leaves in vegetative branches in open areas and upper leaves in fruit branches on different terrain and by different cultivation style. Gas exchange parameters were analyzed with the methods of simple correlation analysis，path analysis，principal component analysis as well. The results showed that leaf Pn of vegetative branches was higher than that of fruit branches in both sunny days and cloudy days. Both of them showed single peak curve. The upper leaves’ Pn of fruit branches was largest, the middle leaves’ in the middle and the underneath leaves’ was the smallest. Upper leaf Pn of fruit branches on flat land was higher than that on sloping land and showed single peak curve. The simple correlation analysis showed that leaf Pn was positively correlated with leaf air vapor pressure deficit, effective photosynthetic radiation, air relative humidity, stoma conductance and intercellular carbon dioxide concentration. The path analysis showed that path coefficients of leaf Pn with leaf transpiration rate and effective photosynthetic radiation were 0.731 and 0.6411 respectively. The principal component analysis showed that contribution of temperature to leaf Pn accounted for 54.27%.