An efficient adaptive stability control for multi-generators power system is presented based on step-ahead model prediction methodology. This control is named the model prediction adaptive control (MPAC) that is built upon optimization of selected performance index defined as weighted combination of generator voltage deviation, mechanical-electrical torque mismatch, and speed incremental. Method of Equivalent Circuit (MEC) is proposed to design the MPAC excitation controller for multi-generators power system. MPAC can realize real-time adaptive control based on the MEC. This paper demonstrates effectiveness of MPAC for improvement of the wide-area power system stability. The proposed MPAC is applied to a four-generator power system with weak interconnection between areas. Simulation results show that the inter-area oscillation after a substantial disturbance on a line connecting two areas can be damped out rapidly. Simulations also show the same efficiency of MPAC for the stability control of multi-generator power system as one of the excitation control with high gain AVR plus fine-tuned PSS.