Abstract: By controlling the plasma spraying process, artificial hole defect and density non-uniform defect were prepared respectively in the interior of the target coating. The water immersion ultrasonic C-scan was used to carry out the defect imaging and waveform analysis. The results show that the testing results agreed well with the artificial defects, thus validating the water immersion ultrasonic C-scan detection had enough defect sensitivity and reliability for production detection of plasma spraying target. This method shows great value for the quality control of spraying target products.