Abstract: An experimental research on underwater high-speed imaging detecting system is discussed in this paper. In lowlight situations, a 532 nm green laser is used as the light source. A high-speed camera is employed to shoot the bubbles underwater. The high-speed camera is 3 m away from the bubbles. Imaging rate of the camera is about 500 fps. Under the conditions of with or without cooperative target behind the bubbles, by changing the rate of the high-speed camera, a lot of images of moving bubbles have been acquired. The bubbles are identified with edge detection techniques. It can be concluded that in the case of with a cooperative target behind the bubbles, the images are clearer and higher in contrast.