In the linear structured light three-dimensional measurement system based on triangulation, how to quickly and accurately extract light strip center from an image is pivotal to real-time and precise measurement. Firstly, the factors influencing light strip center extraction are described, such as linear structured light sources, environmental noise and surface reflectance properties of the measured object. Then the existing methods, including specialized light image de-noising and threshold segmentation technologies, traditional and improved light strip center extraction algorithms, are summarized. The principle and key technology of these algorithms are analyzed. Finally, some advices aiming at problems appearing in the existing methods are given, and it is pointed out that the developing monocular laser systems which can handle with high pixels image and can be used in outdoor light and complicated natural environment are the development trend in the future.