Abstract: 【Objective】 To explore the optimal water and fertilizer coupling scheme of the main trunk apple trees under the integrated water fertilizer mode. 【Methods】 Field experiments with random block design of 16 treatments (two levels of phosphorus fertilizer, P₁, 109.5 kg/hm², P₂, 54.75 kg/hm² were perfprmed; two levels of potassium fertilizer, K₁, 199.5 kg/hm², K₂, 99.75 kg/hm²); and four levels of water, W₁, full irrigation, 5,256 m³/hm², W₂, mild deficit, 4,248 m³/hm², W₃, moderate deficit, 1,050 m³/hm², W₄, severe deficit, 840 m³/hm²) were conducted to investigate the response of apple fruit quality under different water and fertilizer coupling schemes. 【Results】 The results revealed that the fruit quality indexes were significantly different among the treatments.The highest comprehensive score treatment of fruit quality was W₂P₁K₁, followed by W₁P₁K₁, and the lowest treatment was W₂P₂K₂. 【Conclusion】 Principal component analysis simplified the seven fruit quality indexes into three key factors, and a comprehensive evaluation system of fruit quality was established. The top five fruit quality rankings under the 16 water and fertilizer treatments were W₂P₁K₁, W₁P₁K₁, W₄P₁K₁, W₃P₁K₁ and W₁P₂K₁, respectively.