Wind and PV power bundled with thermal power and then transmitted is an important approach to delivering power for large renewable power bases. There is a low-frequency oscillation problem of the wind-PV-thermal-bundled power transmission system. Thus a coordinated optimization design strategy based on STATCOM additional POD control is proposed. First, the model of the wind-PV-thermal-bundled power system is built, and the STATCOM-POD controller is designed. The active power of the tie-line is used as the input of the controller. Secondly, based on the Lyapunov stability method, the objective function considering the minimum damping ratio of all low-frequency oscillation modes is constructed. Finally, a genetic algorithm is used to coordinate and optimize the multiple controller parameters to improve the low-frequency oscillation characteristics of the system. With the IEEE 4-machine 2-area system as an example, the correctness and effectiveness of the proposed method are verified. The results show that the stability of the generator speed can be maintained using the STACOM-POD controller with optimized parameters, the system damping is increased, the fluctuation of power network parameters caused by low frequency oscillation is suppressed, and the low-frequency oscillation characteristic of the wind-PV-thermal-bundled power transmission system is improved. This work is supported by the National Natural Science Foundation of China (No. 51607158).