A new calibration method of line laser monocular vision sensor based on a new free position and orientation planar target is proposed for the deficiencies in existing methods. Projective invariance of a set of vector product orientations are applied to sort the image control points and then calculate the correspondence between image control points and target control points. Laser control points in each image are extracted by calculating the intersection points of laser stripe and ordered straight lines connecting control points. 3D coordinates of the laser points in camera coordinate frame are calculated by cross ratio invariance principle. Therefore the sensor is precisely calibrated with the optimization calculation of camera parameters and laser plane parameters. Verified by experiments, this calibration method has high-freedom operation, simple calibration process and ideal calibration accuracy.