Abstract: The current distribution network is faced with problems such as large voltage fluctuations, especially with the increase in the number of distributed power sources, which poses challenges to the quality of power supply. Voltage deviation or fluctuation will affect the use of users" electrical appliances and even cause equipment damage. In order to solve this problem, it becomes very important to study the role of distributed power and energy storage systems. This article mainly studies how to use these two to improve the voltage quality of distribution network. First, the working characteristics of distributed power sources (such as photovoltaic and wind power) are analyzed and it is found that their intermittent output may cause voltage instability. Then the working principle of energy storage systems is discussed, especially how battery energy storage can be quickly charged and discharged to balance power fluctuations. To test the idea, the study established a distribution network model containing distributed power sources and energy storage, and used mathematical tools to optimize their location and capacity. The control strategy uses some algorithms to manage the charging and discharging timing of energy storage. The results found that through reasonable configuration and collaborative control, energy storage can effectively smooth the changes in distributed power output and control the voltage deviation and fluctuation on the line within a reasonable range. The study also selected actual distribution network areas for testing, and the data showed that the voltage qualification rate was significantly improved. These situations show that distributed power generation combined with energy storage has a good effect on improving the voltage of the distribution network, and provides practical experience for engineering applications. Future work can explore more intelligent control methods or multiple energy coordinated operation modes.