Abstract: A design scheme of the optical axis detection instrument for shipborne optoelectronic devices is proposed to overcome the difficulties resulted from environmental limitation and ship stagger during the process of photoelectrical multi-sensors boresight parallelism adjustment in the outer testing locate and loading ship. The coupling of laser and visible-light boresights is realized with common-path and spectrum conversion technologies. The instrument's key part-boresight coupling unit is simulated and analyzed by CAD/CAE. The parallelism errors of 13.576332 and 16.397421 between two reflectors were obtained in the range of -10℃～+40℃. The result of environmental test indicates that the accuracy error of the instrument is less than 20 and meets the design index.