Abstract: In ultrasonic TOFD (time of flight diffraction) collected waves, the lateral wave brings about difficulty in identification of near surface defect signal. To solve this problem, a clutter suppression method using an adaptive filter is presented. Through iterative the parameters, the filter can adjust the reference signal to meet the changes of the clutter wave to be suppressed. Then the clutter wave can be removed and the near surface defect signal can be separated. The principle of clutter suppression method based on adaptive technology is described. The proposed method is studied by using computer simulation technique. Artificial defect collected waves are clutter suppression processed. The results show that the proposed method can effectively suppress clutter and extract near surface defect signal.