Electromechanical wave model is a new method in the research of generator-grid dynamic response of large scale electric power systems. Based on wave equations of elastic bearing transmit mechanical power and transmission line transmit magnetic power respectively, this paper built integrate electromechanical wave model of turbine-generator-grid with the example of No. 3 unit in Yimin Power Plant. With the help of electromechanical wave model, subsynchronous oscillation (SSO) example was given which indicated that the higher disturbance voltage, the bigger SSO amplitude; the larger damp, the smaller SSO amplitude, which will make the fluctuation become stable earlier. This conclusion has significant engineering value on reducing SSO amplitude of Yimin power plant.