Automotive weld gluing can improve the body seal level, and it is necessary to detect the strip and obtain three-dimensional information. Laser triangulation is a widely used detection method. One of its key technologies is to accurately extract the center of the strip. However, for the black detection colloid, the strip center extraction is poorly robust, so an algorithm based on strip segmentation for Hessian matrix positioning and Gaussian curve fitting is proposed. Firstly, the overall image contrast is improved, and the noise is removed by the denoising algorithm. Then the extreme value method is used to locate the light strip, and the Hessian matrix is used to locate the center of the laser strip. Finally, the center of the laser strip is accurately fitted by the Gaussian curve.Experimental studies show that after adding white noise with a noise amplitude of 100 to the light bar image, the precision can be also controlled at the sub-pixel level, and the stability of the light bar of the black detected object can be improved.