With the wide application of flexible AC transmission system (FACTS) in power system, one of the major directions of FACTS development is the research of multi-FACTS coordinated control based on wide-area measurement system (WAMS). The wide area centralized coordination control architecture is established. Based on the structure of the dynamic output feedback control and the theory of the polytopic linear differential inclusion, a wide-area multi-FACTS coordinated control algorithm for multiple load cases is proposed. In virtue of the output feedback signals from WAMS, the delay margin is analyzed within which the algorithm can ensure the stable operation of power system. The algorithm is validated in a 4-machine, 2-area system with static var compensator (SVC) and thyristor controlled series capacitor (TCSC). The result shows that the power system sucessfully runs in strong damping modes in multiple load cases.