With algebra and theory of graph as tools and on the base of description of Oriented Functional Relationship Graph(OFRG) of a machine assembly,the paper introdu ces some concepts,the multistage OFRG,the extension generalized hing,the crossover vectors, the connecting vectors, the vectors of element and component etc.,and provides a set of method for the analysis of the structure of OFRG and the setting up of the system of equations of chain walk.