Abstract: To investigate the effects of water stress at key growth stages on soil moisture dynamics and yield of spring maize, water stress simulation experiment in critical growth period was carried out in Wuwei, a typical arid area. The experiment set up CK (control treatment with sufficient water supply during the whole growth period), T1 (continuous drought during the jointing period until the end of the growth period), and T2 (continuous drought during the tasseling period until the end of the growth period). The results showed that under the influence of water stress, the soil temperature of 0-20 cm and 0-40 cm in T1 and T2 drought treatment was higher than that of CK treatment, and the soil temperature of T2 treatment was higher than that of T1 treatment. After the seven-leaf stage, the soil moisture content of the drought treatment section varied greatly. By the milky stage, the water storage capacity of T1 and T2 treatments decreased by 72% and 57%, respectively. The water stress during the key growth period mainly affected the final yield by affecting the vegetative growth and reproductive growth of spring maize. The T1 and T2 drought treatment yields decreased by 66.4% and 54.2%, respectively, and the yield level WUE decreased by 23.4% and 13.1%, respectively. The research results can provide a basis for the quantitative assessment of the drought in the key growth period of spring maize, and provide ideas for the determination of the ecosystem response threshold.