Abstract: Pulsed eddy current (PEC) nondestructive testing is a new technology developed in recent years, mainly used to detect corrosion of aircraft fuselage lap splices quantificationally, aimed at the problems that variations in the probe lift-off makes signal change resemble as variations of corrosion, joint time-frequency analysis is used in this paper, the result of experimentation shows that time-frequency analysis can describe the characteristic of signal changing with time and frequency, which provide a intuitive approach for the PEC nondestructive testing.