In the laser scanning system based on Articulated Arm Coordinate Measuring Machine (AACMM), the extraction accuracy of laser stripe center and using time directly affects the measuring accuracy and real-time response capability of the whole system. Integration and improvement over the existing algorithms at home and abroad, an optimal threshold method and improved Sobel operator and light strip repaired algorithm are used to complete the light crude extraction with picking up ten pixels. Experiments show that, in the 350 mm × 350 mm measuring range, the measuring error is less 50 μm, the extraction time is less 31 ms, and it can meet the requirements of real-time online system.