[Objective] This study investigates the effects of deficit irrigation on leaf nutrient levels (nitrogen, phosphorus, and potassium), enzyme activities (superoxide dismutase, peroxidase, and catalase), and root-zone soil nutrients (nitrate nitrogen, available phosphorus, and available potassium) during the fruit expansion(III) and coloration-sugar accumulation stages ( IV)of citrus in western Hubei. [Methods] This study selected six-year-old “Ehime 28” citrus trees in the western Hubei region as the research subjects. Full irrigation served as the control (CK: daily irrigation volumes of 4 L and 2.5 L during the fruit expansion stage (Stage III) and coloration-sugar accumulation stage (Stage IV), respectively). Four deficit irrigation treatments were applied during both Stage III and Stage IV: mild deficit (LD: 70% of CK), moderate deficit 1 (MD1: 55% of CK), moderate deficit 2 (MD2: 40% of CK), and severe deficit (SD: 30% of CK). The study aimed to explore the response patterns of soil nutrients, citrus leaf nutrients, antioxidant enzyme activities, and root-zone soil nutrients to water stress under drip irrigation across different growth stages. [Results] (1)The results showed that the IV-MD1 treatment significantly promoted the increase of leaf nitrogen, phosphorus, and potassium content by 5.27%, 2.13%, and 12.42%, respectively, compared to the control. Additionally, the growth rate and accumulation of leaf nutrients reached their maximum under this treatment. (2)The III-MD1 treatment effectively enhanced the antioxidant defense capacity of the citrus trees, with the activities of superoxide dismutase (SOD) and peroxidase (POD) increasing by 63.3% and 104.5%, respectively. (3) The III-MD1 treatment significantly increased nitrate nitrogen and available phosphorus content in the upper and middle soil layers by 74.54%, 17.61%, 73.53%, and 43.58%, respectively. The IV-MD1 treatment also optimized the vertical distribution of soil nutrients, reducing nutrient leaching losses, with available potassium in the upper and middle layers increasing by 59.23% and 51.67%. (4)Canonical correlation analysis revealed significant relationships between soil and leaf nutrient elements. Leaf phosphorus and potassium content were positively correlated with available potassium in the soil, while they were negatively correlated with soil nitrate nitrogen, available phosphorus, and leaf nitrogen. [Conclusion] The IV-MD1 treatment effectively promotes the accumulation of soil and leaf nutrients and enhances the activity of protective enzymes, making it a suitable drip irrigation water-saving management strategy for citrus cultivation in western Hubei. The findings provide a theoretical basis for optimizing citrus irrigation practices and improving fruit quality.