Power system stabilizer is suppressing the low-frequency oscillation of the power system to improve the dynamic stability of the power system. The need of power system stabilizer (PSS) or supplementary excitation control is to apply a stabilizing signal through the excitation system to produce additional damping torque of the generator in a power system at all operating and system conditions. In this paper, the study of the dynamic behaviour and small signal stability of the single-machine infinite bus (SMIB) with CPSS under various loading condition is presented. Simulation result in with and without PSS is resulted is shown.