The invention discloses an extension method of an AXI interconnected bus with the view of solving the technical problem in the prior art that a conventional bus-expansion method is complicated. The technical scheme is characterized in that ID tag extension and maintenance are symmetrically carried by a bus interconnected structure; extended ID tags are utilized in the interconnected bus so that routing, mediation and decoding operation are carried out; RAM tables for extension and maintenance of ID tags are configured so that extension and maintenance of ID tags during an operation process of outstanding; a Master equipment end is only equipped with one fixed ID tag label which cannot be extended or renamed; the Master/Salve equipment end only uses one ID tag for communication so that design difficulty of the Master equipment end is reduced and complexity and expense of the system level design are decreased; in the meantime, a configuration option of an ID tag extended application is added in the interconnected structure so that compatibility with extended design of ID tags maintained by Master is achieved.