To improve calibration accuracy, this paper proposes a light plane calibration method based on a line transformation in space. First, a cross-correlation template and a 5-point moving-average method are used to extract the center of the laser stripe, and the linear regression equation of the light bar in the images is then fitted by the orthogonal regression method. A straight line equation for the target surface light bar is obtained by a plane homography transformation, and the straight line equation in the target coordinate system is converted to Plücker matrix form. According to the pose transformation relationship, the straight line equations in the camera coordinate system are obtained and statically indeterminate line-plane co-planar constraint equations are established. A singular value decomposition(SVD) is used to solve the parameters of the light plane equation. The root mean square (RMS) of the standard step block length obtained by the proposed method is 0.065mm, and the average error is less than 0.030mm. The measured average error of cylinder diameter and RMS are less than 0.050mm. The results show that the proposed method uses the overall information of the light bar itself to fit the light plane, which can achieve higher calibration accuracy. This represents a simple calibration process that avoids the separate solution of each feature point.