Reasonable planning and configuration of distributed power generation (DG) accessing the distribution network can improve system voltage stability while taking into account the interests of operators and users. In this paper, considering economic indicators, a new system voltage enhancement indicator is proposed to improve the overall voltage distribution of the system. A multi-objective optimization model is established, and an analytic hierarchy process is used to determine the weight of each objective function, which is then transformed into a single objective function programming problem. Given the problem that the sooty tern optimization algorithm has relatively strong global search ability but its local search ability is weak, a novel and improved sooty tern optimization algorithm is proposed. It incorporates the genetic algorithm's mutation idea and optimizes the configuration of DG. This improves convergence speed and accuracy. The calculation example verifies that the improved sooty tern optimization algorithm has a good effect on improving the system voltage distribution, and the established model has good practical significance. This work is supported by the Key Research and Development Program of Shandong Province (No. 2019GGX103049).