Abstract: According to the characteristics of the high precise GPS deformation monitoring, basing on the first period observation results of the monitoring network,the similar single-difference model of solving GPS monitor point deformation information at single epoch is built,and the receivers'antenna phase center offsets are discussed.This model avoids the troublesome problem of cycle slip detecting and repairing,and is not only applicable to the static and dynamic monitoring modes, but also suitable for the single receivers.The correctness of the similar single-difference model is verified with the practical data in Three Gorge Area.