Abstract: This essay analyzes the docking of line-replaceable unit (LRU) for some huge laser facilities, where centering and collision issues are pointed out as the key technologies for LRU docking monitoring. The centering technology mainly transforms the three-dimensional problem into two-dimensional one, adopting the characteristic of machine version capturing to analyze the position and posture of LRU. The collision monitoring technology mainly takes advantage of the principle that power is generated in the collision during the process of assembly and calibration. Monitoring force in all directions on the point of collision occurred, which indirectly reflects the degree of the collision, returning feedback to the docking platform after measurement data is analyzed, and amending the docking trajectory of the LRU in time can achieve the light collision docking during the full process of LRU.