Abstract: In this paper, the specimens with artificial defects of different sizes and buried depths were made by using sticking membrane method, inserting steel sheet method, mold release agent method and demoulding cream method respectively, and then the water immersion ultrasonic testing was carried out on them. The results show that the water immersion ultrasonic detection method can detect the artificial defects in composite laminates made by sticking membrane method and inserting steel sheet method effectively, but is insufficient to detect the artificial defects made by mold release agent method and demoulding cream method. The research work in this paper has a certain reference significance for the fabrication of specimens with artificial defect and ultrasonic inspection of carbon fiber composite laminates.