Abstract: The development of distributed energy systems is of great significance for the realization of carbon peak and carbon neutrality,for the promotion of development and utilization of renewable energy. A method for DG site selection and capacity determination in distribution networks is proposed based on bacterial foraging optimization algorithm（BFOA）. Mathematical model and constraints are established to minimize the power loss index,voltage deviation and net operating cost of distribution network. Loss sensitivity factor（LSF）is proposed to determine the DG installation location. BFOA algorithm is used to solve the optimal capacity of DG. Simulation shows that BFOA algorithm has obvious advantages in model solution time and convergence speed compared with traditional optimization algorithms. The proposed planning method can minimize power loss and operating cost and improve the system voltage stability.