The invention discloses a laser marking device and a calibration method thereof, and the method comprises the steps: an inputted to-be-marked pattern are received; according to the coordinates of marking points, a laser marking head is controlled to mark an actual marking pattern; the actual marking pattern is collected through an image collecting device; corresponding relations between the actual marking points in the actual marking pattern and to-be-marked points in the to-be-marked pattern are established, and coordinates of the actual marking points in the actual marking pattern are generated; a first quantity of to-be-marked points are selected from the to-be-marked pattern, and if the coordinates of the selected to-be-marked points and the coordinates of the corresponding actual marking points are same is judged; if not, the selected to-be-marked points of which coordinates are different with the coordinates of the corresponding actual marking points serve as to-be-calibrated points; and coordinates of the to-be-calibrated points are adjusted. According to the above method, the method can make the automatic calibration of the laser marking device avoiding the measuring errors caused by manual calibration, and the measurement precision is provided.