As a key stage in the assembly process of large-scale products, pose measurement has characteristics of diverse methods and complex theory. It is helpful to analyze process of pose measurement theoretically by dividing pose measurement modes according to different measurement principles, and studying characteristics of various measurement modes is of great significance for accurate pose measurement. Firstly, pose of component was divided into absolute pose
and relative pose according to the assembly process of large-scale products. Secondly, by analyzing principle of relative pose measurement, the research of pose measurement mode was carried out, three basic pose measurement modes were defined, and three combination modes were derived on this basis. Finally, the application of pose measurement mode was analyzed with three specific relative pose measurement cases, which provided a theoretical basis for selection and optimization of pose measurement method in large-scale products assembly tasks.