Network structure has a great impact on the realization of complete network control. Therefore, it is of great significance to optimize the controllability of complex networks only based on network structure without adding drive nodes. This paper proposes a method of dividing a static symmetric network into a dynamic time-varying network composed of multiple snapshots(each snapshot is a static network), which uses the advantages of the time-varying network to reduce the number of driving nodes and improve the network controllability. The controllability criteria of the time-varying symmetric network composed of multiple snapshots, the optimal partition of snapshots, and the relationship between the number of drive nodes and the number of snapshots are given. The application process of the partition method is illustrated by an actual example, and the simulation results are verified in the model network and the real network. The results show that the method of time segmentation can effectively reduce the number of driving nodes in the symmetric network and improve the network controllability.