During plant operation, high temperature and high pressure water and steam are flowing at high velocity inside these piping systems. In pipes of power plants, local wall thinning may result from erosion/corrosion(E/C). Therefore, it is important to evaluate the nondestructive characteristics for corroded pipes to maintain the integrity of the secondary piping systems. In this study, the pressure vessel piping with corrosion used during long terms were investigated from the timefrequency analysis method. The damage of piping could be evaluated by ultrasonic parameters such as center frequency and echo waveform. Based on NDE analysis by time-frequency analysis method, it should also be possible to evaluate from various damages and defects in piping members.