Objective Motion analysis of laparoscopic instrument is crucial for instrument design. The space that surgical instrument can reach after entering the abdomen via a small incision is large, however, motion space of the instrument during operation is limited. In this paper, range of motion of the instrument was measured, including inserted length and pivoting angle. Methods Two tasks, transferring and suturing, were set up based on laparoscopic surgery training system. A binocular vision system, Micron Tracker, was used to obtain the position of the marker on the instrument and instrument tip during task operation. A new coordinate system was established based on the operation platform. The inserted length and pivoting angle of the instruments were calculated afterwards. Finally, a general formula of instrument motion space was obtained. Results In transferring task, motion space of left and right instruments were almost symmetrical. The inserted length was approximately 154 to 240mm. Up/down pivoting angle was approximately 29 deg. Left/right pivoting angle was approximately 30 deg. In suturing task, there was a big difference of motion space between left and right instruments. Up/down (45 deg) and left/right (52.2 deg) pivoting angles of right instrument were much bigger than those of left instrument (up/down 27.7 deg, left/right 34.7 deg). In addition, instrument motion space in suturing task was larger than that in transferring task. Conclusions Actual motion space of the instrument during operation is smaller than theoretical value. Operation tasks, location of the insert point, and left-right hand are important factors to determine actual motion space. The study can be used not only for motion analysis of instrument for traditional laparoscopic surgery, but also for motion analysis and instrument design via different surgical incisions.