Probability of determining whether the designed generation system will work efficiently has become an important concern for power system engineers. In case of predetermined failures, power system operators can make provisions for backup generation systems and prevent blackouts. Thus reliability analysis of power system is an important task. To simplify the reliability calculations, graphical user interface model has been developed. The existing methods of reliability evaluation are complicated but graphical user interface provides a pictorial view and takes system inputs from the user. Every step of calculation is displayed. This model can be useful for beginners as well as experts.