Abstract: 【Objective】 This project aims to study the causation of walnut wihtered leaf symptom in southern Xinjiang. 【Methods】 In this research, an inter-garden survey was carried out on walnut trees with withered leaf symptom. By collecting samples of normal and bad walnut leaves, soil samples from the root area and samples of irrigation water, element content characteristics were determined and element content differences were statistically analyzed. The causes of walnut withered leaf symptom were systematically analyzed combined with meteorological data. 【Results】 The peak period of the incidence of walnut withered leaf symptom was from the end of July to early August, mainly concentrated on both sides of the highway and young trees less than 5 years witnessed serious incidence. There were distinct differences of chlorin ion, natrium ion and magnesium ion between bad leaves and normal leaves. The content of chlorin ion magnesium ion in bad leaves was 37.54, 16.77 g/kg, remarkably higher than normal leaves. The content of magnesium ion in bad leaves was 2.27 g/kg,remarkably lower than normal leaves. The content of phosphorus ion in bad leaves was higher than normal leaves at 0-20, 20-40 cm soil layer, 17.78 and 18.47 mg/kg respectively.The enrichment of chlorin ion and calcium ion in the leaves were not from irrigation water. 【Conclusion】 From the research above, the incidence of walnut withered leaf symptom was mainly caused by the high temperature, arid air and shortage of precipitation in walnut garden. With the strong transpiration and postponed irrigation, the leaves lost water quickly. This has led to the damage of the leaves function and the imbalance of elements proportion, which ultimately caused withered leaf symptom.