A　new　method　was　introduced　to　accurately　detect　the　defects　of　time　of　flight　diffraction　(TOFD)　D　scanning　image.　First,　the　clutter　suppression　algorithm　based　on　energy　distribution　was　used　to　remove　direct　wave　and　reflected　bottom　wave.　The　background　clutter　could　be　removed　through　algorithms　of　binarization　processing,　edge　detection,　corrosion,　clustering　and　removal　of　small　clusters.　Then,　a　parabola　was　fitted　through　the　least　square　method,　and　ordinate　vectors　of　feature　points　and　fitted　points　were　on　the　correlation　processing.　With　the　matching　degree　of　defects　and　parabola,　the　defects　could　be　detected.　The　results　demonstrate　that　the　proposed　method　was　effective　and　accurate.