In this experiment, the drought-tolerant soybean variety Heinong 44 and the sensitive soybean variety Heinong 65 were used as experimental materials to study the effects of drought stress and re-watering on the osmotic adjustment ability and yield of soybean. The results showed that given a normal water supply, the proline and soluble protein contents of Heinong 44 and Heinong 65 showed an increasing trend during the growth process, while the soluble sugar content increased and then decreased. The contents of proline, soluble protein and soluble sugar increased significantly with increasing drought stress, and the magnitude of increase of Heinong 44 was higher than that of Heinong 65. The osmotic adjustment ability of the drought-tolerant variety was significantly higher than that of the sensitive variety and showed consistent performance at different stages. After re-watering, the proline and soluble sugar contents of the flowering and pod-setting stages and the soluble protein content of the seedling stage were restored to the control levels. Drought stress resulted in a decrease in the effective pod number, pod number per pod, 100-grain weight and yield. Severe drought had the greatest impact by increasing stress and decreasing soybean yields, which were followed by the flowering, bulging and seedling stages.