Abstract: Taking ‘Yanfu No.3’ apple introduced from Aksu region of Xinjiang as the test material, the effects of different N,P and K combined application treatments on the growth of branches and leaves, light distribution and photosynthetic characteristics of ‘Yanfu No.3’ apple at the early fruit stage were studied by using portable photosynthesis instrument and portable SPAD chlorophyll meter with different fertilization rates set by furrow water-soluble fertilization method.The effects of different N,P and K ratios on leaf curtain change, leaf SPAD value and photosynthetic characteristics were compared at fruit setting stage（late April）,physiological fruit drop stage（mid June） and fruit enlargement stage（early August）,in order to provide reference for the fertilization management of ‘Yanfu No.3’ apple in Southern Xinjiang.The results showed that the SPAD value of leaves was positively correlated with nitrogen and potassium application rates.Phosphorus fertilizer could effectively improve leaf area and increase branch length.There was a significant negative correlation between leaf area and SPAD（r=-0.758）.Increasing branch length by phosphorus application would lead to an increase in tree canopy density, thereby affecting light.There was a significant negative correlation between branch and tree light（r=-0.538）.Different fertilization treatments could affect the growth status of apple branches and leaves, SPAD value of leaves, and photosynthetic parameters, and the differences among the data groups were significant（P＜0.05）.Appropriate amount of phosphorus was beneficial to increase Pn of apple leaves.To sum up, different fertilization treatments would affect the photosynthetic characteristics of leaves.From fruit setting stage to expansion period（late April to early August）,the best ratio was N fertilizer 534.77 g · plant^-1,P₂O₅ fertilizer 652.17 g · plant^-1,K₂O fertilizer 588.23 g · plant^-1.