The new type ligand, bisphosphonites, were easily prepared through ligand exchange reaction of bis (diethylamino)phosphine with diols. These bisphosphonites reacted with (COD)²Rh^+BF₄^- to corresponding bisphosphonite-rhodium(I) comlexes, of which X-ray crystallography was for the first time investigated. This organometallic compound was applicated in hydroformylation reaction as catalyst, and proved to be very effective one.