The power transmission network (PTN) and the natural gas transmission network (GTN) are interdependent more closely with the fast development of gas-fired units and electricity-driven gas facilities, bringing about challenges to the restoration of the coupled system. During the restoration process after a major power outage, the availability of gas-fired units is affected by the supply of natural gas. Meanwhile, the restoration status of electricity-driven gas facilities depends on power supply, and further influences the gas supply of gas-fired units through gas dynamic transmission process. In this paper, a model is proposed to determine the restoration sequences of generators, considering the interdependency of the two networks and the dynamic characteristics of the GTN. The objective is to maximize the system generation capability of the PTN. The operational constraints of the PTN, GTN, and coupling facilities, together with the natural gas dynamic constraints are formulated. Considering the independent management and information privacy of the two systems, a distributed optimization algorithm is adopted to solve the model. In the decentralized GTN model, the nonlinear dynamic constraints of natural gas are transformed into second-order conic constraints, allowing the model to be efficiently solved by off-the-shelf solvers. The effectiveness and superiority of the proposed method are verified using PTN and GTN coupled systems.