In the development and application of superduty lathe process, the size measurement of a large workpiece is a key issue of quality control because the cutting process of large workpiece is high linear speed and time-consuming . A novel surface position information acquisition method for rotational object is proposed. The method uses high speed linear CCD to acquire image sequences, adopts image restoration technique to resolve clear images of laser spot from the image sequences, identifies sub-pixel center point of laser spot with correlation information among the clear frame-to-frame images, then resolves surface position information of rotational object with triangulation principle. Therefore, defects of existing laser triangulation for high-speed rotational object measurement are overcome. According to the resolved surface position information of rotational workpiece, the stability of accuracy, tool wear and vibration characteristics of superduty lathe can be evaluated.