The invention provides a method and a device for estimating the covering precision of a multipoint positioning system. The method comprises the following steps of: acquiring the coordinate data of a building of the airport ground and the coordinate data of a receiver; obtaining an effective estimating area according to the coordinate data of the building; and calculating the covering precision of an estimating point according to the coordinate data of the receiver and the effective estimating area. The device comprises an acquiring module, an estimating area obtaining module and an estimation calculating module. The embodiment of the invention realizes the effective estimation on the covering precision of the multipoint positioning system under the condition of serious non-visible distance so that a user can obtain the influence of the placing geometric distribution of all far-end receiving stations on the precision of the multipoint positioning system and guide a receiver geometric distribution station of the multipoint positioning system.