Photovoltaic access will change the structure and operation mode of distribution network, increase the risk of node voltage exceeding the limit, and have a negative impact on the safe and stable operation of distribution network. Therefore, an improved PSO multi-objective optimization algorithm is proposed in this paper. The simulation results show that the algorithm can find a balance between the access of photovoltaic and the risk of voltage overrun in distribution network. It can not only access photovoltaic as much as possible to improve economic benefits, but also ensure that the risk of voltage overrun in distribution network is low.