Abstract: According to the construction features of conventional island of nuclear power plant, test blocks with artificial defects were designed and manufactured. The TOFD, X-ray and conventional ultrasonic detection on the test block were performed. The detection results from the detection rate, defect location and quantification of defects and defect rating were compared and analyzed. Results show that the TOFD technique in pipeline detection is of high detection reliability. By means of TOFD and radiographic testing in engineering, the application of TOFD technology in conventional island of nuclear power plant is feasible.