In order to improve the accuracy and efficiency of line structure light plane calibration and the universality of the calibration method, a line structure light plane calibration method based on a 2-D circular target was proposed. The subpixel coordinates of the center point of the light strip irradiated at any position of the 2-D circular calibration target were obtained by the light strip extraction algorithm. All the points on the light strip were fitted into a straight line, and the lines connecting each column of the circular calibration target intersected at one point. After obtaining the intersection point of each column of the calibration target line and the fitted light strip center line, a line connecting the intersection point and the camera optical center was formed. By setting up the equation of the line and the equations of two intersecting lines in the pixel coordinate system, and the equation of the plane where the 2-D circular calibration target was located, the coordinates of each intersection point in the camera coordinate system are solved. Finally, the plane fitting algorithm of least squares was used to obtain the equation of the light plane. The basic principle and implementation process of the calibration method was introduced, and the validity of the method was verified by setting up the experimental system. The results show that the average measurement error of the light plane obtained by this method can reach 2.36737 mm, which has high robustness, and the calibration process is very simple and suitable for general engineering applications and machining processes. This study provides a reference for the light plane calibration of line structure light sensors.