Abstract: Objective: to analyze the influence of different soil layer thickness on the water condition and growth of locust in dry season, to determine the appropriate soil layer thickness and promote the rapid growth of locust in dry season. Methods:The artificial acacia forest born in 25 years was selected as the research object, and three plots with different soil layer thickness were set, namely the soil layer of 20~30cm thickness, the 40~50cm thickness soil layer, and the soil layer of 60~70cm thickness.Results: on the whole, the thicker the soil layer is, the better the moisture status and growth status is; dry season soil moisture content, early morning branched water potential with the decrease of soil thickness, stomatal conductivity and maximum photosynthetic rate decreases with the decrease of soil thickness, and instantaneous water utilization efficiency increases with the decrease of soil thickness, locust leaf area increases with the decrease of soil thickness, locust tree height and chest diameter decreases with the decrease of soil thickness. Conclusion: the greater the soil thickness, the more the water of the soil can in the dry season.