FACTS technology has considerable applications in power systems, such as; improving the steady stateperformance, damping the power system oscillations, controlling the power flow, and etc. STATCOM is oneof the most important FACTS devices used in the parallel compensation, enhancing transient stability andetc. Since three phase fault is widespread in power systems, in this paper STATCOM is used to improve thetransient stability of power system when three phase fault occurred. Neural Network has been used foradjusting the gain of the supplementary controller of STATCOM. The simulation performed in MATLAB /Simulink software. Simulation results showed when STATCOM combines with proposed Neural Networkbased supplementary controller; the transient stability of power system improves. Manuscript profile