On the design of optimal network topology based on the graph theory，the reliability and real-time demands of information transmission in the wide area measurement system（WAMS）are satisfied.Connectivity is used as the invulnerability measure and hops as real-time measure to develop the communication network optimal model that can meet the constraint requirements at minimum cost.The improved cut saturation algorithm（ICSA）is used to solve the model，and the network optimal topological architecture is obtained under the WAMS flow conditions and performance constraint.It is shown by an example that，under identical constraint condition，the load-balancing capability of the structure is slightly inferior to that of the bidirectional circular topological structure，but the cost is reduced by about40percent.The model and algorithm could provide a certain theoretical basis of network topology optimal analysis and guiding reference for the network topology optimal design of communication network in WAMS.