Abstract: Along with the increase of the permeability of distributed photovoltaic (abbr. PV) generation in distribution network, the voltage out-of-limit in distribution network caused by the fluctuation of load and PV output became increasingly severe. For this reason, a distribution network voltage control strategy based on the collaborative optimization of distributed PV cluster was proposed. Firstly, by means of electrical distance modularity index the distribution network was divided into clusters. Secondly, by use of reactive voltage sensitivity matrix the dominant nodes of each cluster were selected and the voltage status of each cluster was decided by the degree of voltage deviation. The local control mode was applied to voltage regulation of the PV inverters in dangerous clusters and the variable power controller mode was applied to the PV inverters in within safety clusters. Utilizing the reactive voltage sensitivities among clusters the cooperation of safe clusters with dangerous clusters was conducted to make the voltage of entire distribution network operated within the safety margin. Finally, the results of computing example of a certain actual distribution system with 41 nodes show that the results from PV cluster coordinated optimization based-voltage control strategy of distribution network is much better than that from unified droop control strategy and that from unified power optimization control strategy, besides, the voltage quality of distribution network can be effectively improved.