The dense stereo matching in underwater binocular stereo vision imaging does not meet the epipolar constraint in air. To address this issue, an underwater corresponding point matching and the 3D measurement method are proposed. The stereo image collected by the underwater binocular camera can be corrected to an image pair conforming to the principle of coplanar line alignment. Then, the display image of the underwater left and right cameras can be obtained by applying the mature stereo matching method in the air to realize the 3D reconstruction of the underwater target. Firstly, the sum of all the light entering the camera is regarded as a light field, and each light is modeled by a 4D light field expression. Based on this, the plane refraction imaging model and the binocular stereo vision model of the camera are established, and the direction vector of the light is calculated. According to the light field expression, the light is transformed into the form of a point vector, the pixel coordinates of any image point on the direction image corresponding to the original image are calculated, and the position mapping relationship is determined. Through interpolation, the left and right images in line with the line alignment principle can be quickly obtained. Finally, the display map corresponding to each light is obtained. Simulation results show that the line alignment error of the direction image is less than 0. 8 pixel. In the pool experiment, the ball calibrated in advance is used as the target, and the random scattered point active projection is used to increase the texture information of the target surface. The root mean square error of multiple measurements of the target ball is 2. 8 mm, which has high measurement accuracy.