This paper presents a new method for coordinately tuning the parameters of UPFC controller and power system stabilizer (PSS) as well as determining the PSS location to enhance the stability of power system by using a new hybrid particle swarm optimization based co-evolutionary cultural algorithm, so called culture-PSO-co evolutionary (CPCE). Nonlinear simulations are implemented on the IEEE 39-bus power system. The results imply the effectiveness of the proposed method for damping out power system oscillations.