In order to extract the center of laser stripe accurately in noisy environment, the improved gray-scale weight model was adopted to extract subpixel centers of laser fringes. The image acquired by 3-D laser imaging system was processed by means of mean threshold method and the improved gray weight model. The method was compared with the traditional algorithm. The results show that, the algorithm can extract laser fringe region more completely. The average fitting correlation coefficient is 0.9809 (closest to 1). The maximum difference of average column coordinates is 0.4518pixel (closest to 0). The average coefficient of variation is 0.0062 (closest to 0). Compared with other methods, it has better results. It can suppress the influence of multi-noise environment on laser stripe extraction and extract subpixel centers of laser fringes accurately. It has good robustness. The algorithm provides a reference for extracting the center of laser fringes accurately.