The effects of N₀P₀K₀,N₀PK,NP₀K,NPK₀ and NPK on the photosynthetic characteristics and fruit qualityof the seven-year-old"Hongzaosu"pear were studied,so as to provide a reference for rational fertilization in agri-cultural production.The results showed that nitrogen fertilizer have a great influence on net photosynthetic rate,sto-matal conductance and water use efficiency.Phosphate fertilizer have a great influence on transpiration rate andsaturation vapor pressure difference,and potash fertilizer have a great influence on intercellular CO₂ concentration.The net photosynthetic rate,transpiration rate,stomatal conductance,intercellular CO₂ concentration and water useefficiency of the leaves with NPK were increased by 87.76%,69.95%,104.81%,78.68% and 57.14%,respectively,compared with N₀P₀K₀.The effect of potassium deficiency on soluble solid,total acid and soluble sugar content wasobvious.The net photosynthetic rate was positively correlated with stomatal conductance,water use efficiency andfruit diameter,and intercellular CO₂ concentration was significantly positively correlated with fruit diameter,solublesolid content and total acid （P＜0.05）.