This chapter proposes a coordinated operation framework of power-communication coupling networks for dispatching large-scale flexible loads to provide operating reserve. A power-communication equivalent model is established to couple the regulation power and transmitted data from flexible loads. The data nodes and branches in the communication network are formulated equivalently with power nodes and branches in the power network. On this basis, considering spatially and temporally dynamic power-communication coupling networks, the power flow and communication flow are coordinately optimized to minimize the regulation costs and communication costs. The proposed scheme is validated based on the 5-bus and 118-bus power-communication coupling networks. Numerical results illustrate that the coordinated optimization framework reallocates operating reserve capacities and decreases the regulation cost of power-communication coupling networks.