Abstract: To cope with cyber-physical coupling failures of the power transmission system, a cyber-physical collaborative restoration strategy for a power transmission system subject to communication failures is proposed. First, a restoration model of the physical system is established based on the restoration characteristics of generators, power lines and loads, and with the system security constraints including system frequency, bus voltage, and branch capacity comprehensively considered. Next, a cyber restoration model is proposed based on the network topology of the cyber system. Then, the interactions between physical and cyber systems are modeled by utilizing the operation time delays of power output adjusting of generators, power line restoration,and load pickup due to communication failures. The above three models can be integrated into a mixed-integer second order cone programming（MISOCP） model through the linearization of the power flow. Finally, the feasibility and effectiveness of the proposed method are demonstrated by a sample cyber-physical transmission system modified from the IEEE 30-bus power system.Case Study results indicate that the proposed collaborative restoration strategy manifests its superiority in avoiding additional outages, accelerating system recovery and reducing outage losses.