This paper presents the stability and power-flow control results of a multi-machine power system connected with a hybrid offshore wind farm (OWF) of 160 MW through a unified power-flow controller (UPFC). The q-d axis equivalent-circuit model is employed to establish the complete system model of the integration of the hybrid OWF, UPFC and the multi-machine power system under three-phase balanced loading conditions. Steady-state performance of the proposed UPFC on power-flow control of the studied system is evaluated. Transient simulation results under a three-phase short-circuit fault are also performed. It can be concluded from the simulation results that the proposed UPFC can achieve power-flow control and render damping to suppress oscillations of the studied multi-machine power system connected with the hybrid OWF under various operating conditions.