Abstract: 【Objective】 Analysis the suitable lower limit of soil moisture during the main growth stage of spring oil sunflower irrigated with drip irrigation in northern Xinjiang. 【Methods】 With oil sunflower (Aidatou 858) as test material, using orthogonal design, the same upper limit of soil moisture field capacity(FC) and three lower limits of soil moisture (55%FC, 65%FC and 75%FC, ) were set in the stage of elongation, budding and blossoming, and with local farmers irrigation as control. The effect of different treatments on plant height, leaf area index (LAI), yield and quality of spring oil sunflower was studied. Then the best treatment was chosen based on the entropy weighted -TOPSIS comprehensive evaluation method. 【Results】 The results showed that the plant height and leaf area index of 55% FC were 10.77%, 4.80%, 0.61% and 46.17%, 20.56%, 17.21% lower than those of 75% FC at jointing stage, squaring stage and flowering stage, respectively. The increase of soil moisture lower limit in each growth period was beneficial to promote the increase of plant height and leaf area index of oil sunflower. The yield (5189.33 kg/hm²) and water use efficiency (1.31 kg/hm³) of T₃ treatment were the highest, which were 6.85%-39.75% and 18.88%-47.19% higher than those of other treatments, respectively. The fat content (49.67 g/100g) and protein content (4.84 g/100g) of T₄ treatment were the highest, which were 1.28%-11.17% and 4.61%-27.62% higher than other treatments, respectively. The comprehensive index evaluation based on entropy weight-TOPSIS showed that T₃ treatment was the best. 【Conclusion】 The lower limits of soil moisture suitable for drip-irrigated spring oil sunflower in northern Xinjiang at jointing stage, squaring stage and flowering stage are 55%FC, 75%FC and 75%FC, respectively.