Abstract: An instrument for locating and overlapping pulse laser beams in LRIMS is introduced in this paper. In the instrument, a synchronous CCD camera is used to expose different time for lasers and background to capture the image. This method solves the problem of getting the image of lasers and background at one time with video CCD camera because of too much light-strength difference of them. At the same time, a new locating method with four-quadrant detection is studied to accurately overlap the pulse laser beams.