Abstarct: Power System Stabilizers (PSS) have very important role in power system, so their design methodology has been interesting issue for writing many papers in last decades. Conventional method of PSS design is time-consuming while the methods which are baxsed on single objective optimization or assign a weight to objective have some problems. The present work, discusses some new and fast methods for PSS design which are game theory baxsed multi-objective approaches. In the first method minimization of the values of the settling time and amplitude variations of a response are taken as the goals or two objectives function when designing the PSS parameters. In the second approach, maximization of the minimum damping factor and minimum damping ratio of the system’s dominant oscillatory modes are two objectives. SPEA and NSGA-II are the methods which use cooperative game concepts and generate a set of optimal parameters called Pareto-optimal set. This provides an excellent negotiation opportunity for the system manager, manufacturer of the PSS and costumers to pick out the desired PSS from a set of optimally designed PSSs. Another approach is Nah GA which is baxsed on non-cooperative game and gives an optimal design known as Nash equilibrium. The proposed approaches are implemented and examined in two familiar systems; two-area four machine system of Kundor and a single machine infinite bus system. Different faults are applied to the systems with optimal PSSs and a comparison between the proposed method and other techniques are given which is interesting.