In order to ensure the safe and stable operation of the distribution network, a dynamic reconfiguration method of distribution network based on Partitioning Around Medoid (PAM) time division is proposed. The dynamic reconstruction model of distribution network is established based on network loss, voltage offset and load balance. Aiming at the time division problem in the process of dynamic reconfiguration of distribution network, a method of PAM time division based on dissimilarity is presented. To improve the searching ability of the Cooperative Particle Swarm Optimization (CO-PSO), the velocity updating formula is modified and the normal distribution random adjustment factor is introduced to improve the CO-PSO. The IEEE33 node system is calculated and analyzed. The calculation results verify the validity of the above method. This work is supported by Science and Technology Research Program of Chongqing Education Commission (No. KJ1709225).