The renewable energy connected to the sending-end power grid is increasing rapidly. This paper proposes a coordinated voltage control strategy based on Model Predictive Control (MPC) for renewable power plants of wind and solar power connected to the weak sending-end power grid. Wind Turbine Generators (WTGs), Photovoltaic Arrays (PVAs) and Static Synchronous Compensator (STATCOM) are coordinated to keep voltages within the feasible range during operation, which makes full use of the reactive power capability of WTGs and PVAs. Besides, the impact of active power outputs of WTGs and PVAs on voltage control are taken into consideration because of the high R/X ratio of the collector system. To improve the computation efficiency, an analytical method is used for the calculation of sensitivity coefficients. A renewable energy power plant with 80 WTGs and 20 PVAs connected to a weak sending-end power grid was used to verify the proposed voltage control strategy.