Aerospace products with many varieties, small quantities and high assembly process requirements, are usually assembled manually, which brings a very high demand on assembly operators. In order to provide cognitively comprehensible assembly operation guidance for operators, both operation instruction and on-site operation experience have been analyzed, and then a process information modeling method for on-site aware augmented reality (AR) operation guidance system has been studied. On the basis of computer vision techniques of object recognition, behavior recognition and 3D object tracking, a prototype system for aerospace product assembly operation training has been implemented, realizing both on-site AR guidance and automatic operation recording, which improves the efficiency and accuracy of manual operation tasks.