As an emerging technology,satellite difference positioning technology has all the characteristics of GPS.It can work on a single unit without setting up a base station on land.Its base station is the Inmarsat.MarineSTAR for example,cover a wide range.This article combines an overseas project,aiming at the problem that it is not appropriate to use conventional methods to set up a base station for survey in the measurement area,and the principle and method of satellite difference positioning technology are studied.By comparing the known points and random inspection with conventional measurement methods,it is showed that the satellite difference positioning technology can be applied to large-scale bathymetric survey.Because there is no need to set up a base station,the work efficiency of the technology is greatly improved.