Abstract: A method for measuring thickness or defect depth by pulsed infrared thermal wave technology is described. The method includes heating a measured object by pulsed heating devices, and at the same time, obtaining a thermal image sequence on the surface of the measured object by an infrared thermography device, and storing the thermal image sequence in a general-purpose memory. The method also includes multiplying a temperature-time curve at every point of the thermal image sequence by a corresponding time, thereby obtaining a new curve. The method also includes calculating a first-order differential and obtaining a peak time thereof. The method also includes use of one or more formulas to thereby determine the thickness or the defect depth of the measured object.