The technology of navigation positional service is more and more becoming an integral part of intelligent living fallowing with of the Global Navigational Satellite of System(GNSS), which is achieved rapid development. Especially the high accuracy positioning technology is so that. The text proceeds from BeiDou Wide Area Decimeters System and adopts the method of fault tree analysis according to the phenomenon of pseudo-range layering between deferent satellites by a GNSS receiver. A method of pseudo-range deviational correction is improved after the fault tree. The results show that the method has an obvious weakening effect to the pseudo-range layering.