With the widely application of information and communication technology in the grid, the Cyber-Physical Power System (CPPS) tightly integrating power grid and cyber communication will facilitate the low frequency oscillation Control of wide-area power system. Based on the mass data of power system, this paper proposes a Wide-Area Damping Control (WADC) strategy of CPPS. It first uses variable forgetting factor least square method to identify the physical system model online. Then a Generalized Predictive Control (GPC) algorithm is employed to generate predict instructions based on the identified model. At the same time, a communication compensation mechanism is built to overcome the adverse impacts of cyber system, such as delay, packet loss, and out-of-order. Later, a CPPS co-simulation model combined Matlab with Visual Studio is established to analyze the interaction between power system and cyber system. At last, simulation studies undertaken on a 16-machine 5-area power system show that the proposed co-simulation model can emulate the interaction in CPPS. Also, the proposed CPPS controller can damp inter-area oscillations effectively, even under the negative impact of information system. This work is supported by National Natural Science Foundation of China (No. 61233008 and No. 51520105011).