Abstract: To optimize the topology of low-voltage network so as to take advantage of electric power efficiently is of importance to the research on solar photovoltaic power systems. An approach is therefore presented that the power supply zone of a solar photovoltaic power station should be divided into several subzones by the K-means clustering algorithm, then the topology of network is optimized with the improved minimum spanning tree algorithm in every subzone. Simulation results showed that the line loss of low-voltage network decreases, which thus improved greatly the utilization of electric power.