The speed and accuracy of extracting the center of line structured light has a direct effect on integral performance of the system in three-dimensional measurement of line structured light. Based on geometrical center method, direction template method and barycenter method, a high-speed algorithm of extracting the center of line structured light was proposed. First, the image was preprocessed, and the center of line structured light was fast extracted as contour line by geometrical center method. Then a normal detection method based on location was designed to extract normal direction of contour line. Compared with direction template method, the calculating speed of the proposed algorithm significantly improved. Finally, the center of structured light was extracted precisely through gray weight of normal direction pixel on contour line. The experimental results indicate that the proposed algorithm's speed has significantly boosted in processing, and its precision reaches sub-pixel level.