The stability of an interconnected power system is its ability to return to normal or stable operation after having been subjected to some form of disturbance. Transient stability analysis has recently become a major issue in the operation of power systems due to the increasing stress on power system networks. This problem requires evaluation of a power system's ability to withstand disturbances while maintaining the quality of service. This paper introduces a method as an accurate algorithm to analyze transient stability for single and multi machine system.