Aiming at the high-speed image acquisition of workpiece surface online detection, a workpiece image high-speed online acquisition method was produced. The quantitative relationship between the positioning accuracy in the high speed online image acquisition,motion blur, exposure time, and the speed of workpiece was analyzed. The effect between the vibration of the workpiece and transfer mechanism was analyzed. An image acquisition sequence was designed. Fast trigger was implemented by photoelectric sensor. The accurate positioning was implemented by using the high accurate time delay module, controlling the motion blur by reducing the exposure time. A high-speed image acquisition system was designed based on the high-speed image acquisition method. The positioning accuracy was less than 0.1 mm,and the motion blur was less than 1 pixel, ensuring the accuracy of the workpiece positioning and image quality. It is advantageous to the quality detection of workpiece surface.