The invention discloses a method and a system used for providing position information, which can be used to solve the problem of the prior art of the inability of realizing the large-scale high-precision real-time positioning. The method is characterized in that the access to various CORS data processing centers can be realized by adopting a set time interval according to pre-stored CORS data processing center attribute information, and the differential correction values of various reference stations belonging to the CORS data processing centers can be acquired; approximate position information reported by a target terminal can be acquired; the map grid cell of the target terminal can be determined based on the pre-stored map having the divided grid cells according to the approximate position information reported by the target terminal; according to the acquired differential correction values of various reference stations, the differential correction value of the map grid cell of the target terminal can be determined, and the approximate position information of the target terminal can be corrected, and then the accurate position information of the target terminal can be acquired, and therefore the high-precision real-time positioning of the terminal can be realized.