In order to overcome the shortcomings of the aiming system in inertial confinement fusion device, such as small field of view, long preparation time and large manual interpretation error, a vision aiming system based on diffraction effect is designed. After the diffraction of the reflected light of the target, the starlight detection device is used to detect the center of the target automatically, which reduces the manual interpretation error. The system uses forward illumination to improve imaging integrity, uses quarter-wave plate and polarization splitter to improve system energy utilization, uses diffraction effect and starlight detector to improve aiming accuracy up to 9.52μm, which reduces preparation time. The quality of illumination system and diffraction system is evaluated by using spot diagram in Zemax, and the simulation of the system is carried out. The results meet the engineering requirements. © 2023 SPIE.