The optimization of travel for time-varying transit network based on the environment of subway is realized through the establishment of graph theory model. First, bus and subway network graph, bipartite graph and mapping network graph which is based on the network graph are established. The weight between two subway stations is appropriately reduced in order that we can optimize subway. Meanwhile, time variation of bus and subway is considered in this paper. Whether the time we travel is in their operational period is directly related to the optimal path queried. Then, the optimal path selection algorithm based on the purpose of less transfer times and short distance is given. Finally, we use a numerical example to illustrate the solution process of the proposed method.