One of the causes of centrifugal pump instability lies in the phenomenon of cavitation. Cavitation in the centrifugal pump can produce undesirable effects such as deterioration in hydraulic performance. In order to prevent the emergence of cavitation, it is required to know the onset point of the cavitation, in the pump. Our study presents the process and result of the cavitation measurement performed on a centrifugal pump in a closed loop test system. In this study, we applied CFD analysis, which serves as a means of measuring flow in the impeller of the centrifugal pump. The results gained from CFD analysis correspond, approximately, to the measured results.