Abstract: 【Objective】 This paper investigates thoroughly the effects of different water and nitrogen treatments on the growth, quality and water and fertilizer utilization efficiency of alfalfa, and provides reference for the scientific formulation of a rational application of water and fertilizer management system suitable for alfalfa in Xinjiang. 【Methods】 A field experiment was conducted with three irrigation gradients as W₁ (3,750 m³/hm²), W₂ (4,500 m³/hm²) and W₃ (5,150 m³/hm²) and five nitrogen application gradients as N₀ (0 kg/hm²), N₁ (90 kg/hm²), N₂ (150 kg/hm²), N₃ (210 kg/hm²) and N₄ (270 kg/hm²), and each treatment was replicated three times to study the effects of different water and nitrogen treatments on the growth, quality and water and fertilizer utilization efficiency of alfalfa. 【Results】 Suitable water and nitrogen treatments significantly promoted the growth and yield of alfalfa, and the plant height of alfalfa showed a trend of increasing and then decreasing with the increase of nitrogen application. The highest yield was obtained with W₂N₃ under the synergistic effect of water and nitrogen. Irrigation, N application and water-N interaction had significant effects on crude protein, crude fat content, neutral detergent fiber, acid detergent fiber and crude ash of alfalfa. There were different effects on nitrogen content, nitrogen uptake, nitrogen fertilizer bias productivity, nitrogen utilization, nitrogen fertilizer agronomic efficiency and water use efficiency of alfalfa plants. The combined scores showed that the highest combined scores were all under W₂N₃ treatment. 【Conclusion】 Different water and nitrogen treatments all had certain effects on the growth, quality and water and nitrogen utilization efficiency of alfalfa, and W₂N₃ (irrigation volume of 4,500 m³/hm² and nitrogen application rate of 150 kg/hm²) under water and nitrogen treatments has the best effect.