The invention relates to a systematic calibration method of a welding robot guided by a line structured light vision sensor, which comprises the following steps: firstly, controlling a mechanical arm to change pose, obtaining a round target image through a camera, accomplishing the matching of the round target image and a world coordinate, and then obtaining an internal parameter matrix and an external parameter matrix RT of the camera; secondly, solving a line equation of a line laser bar by Hough transformation, and using the external parameter matrix RT obtained in the first step to obtain a plane equation of the plane of the line laser bar under a coordinate system of the camera; thirdly, calculating to obtain a transformation matrix of a tail end coordinate system of the mechanical arm and a base coordinate system of the mechanical arm by utilizing a quaternion method; and fourthly, calculating a coordinate value of a tail end point of a welding workpiece under the coordinate of the mechanical arm, and then calculating an offset value of the workpiece in the pose combined with the pose of the mechanical arm. The systematic calibration method of the welding robot guided by the line structured light vision sensor is flexible, simple and fast, and is high in precision and generality, good in stability and timeliness and small in calculation amount.