Abstract: To improve the precision of terrestrial networks by using high precision results of GPS positioning,it is at first necessary to choose an appropriate model for the transformation between different coordinate systems.A planimetric rectangular coordinate system is usually used for engineering surveying(e.g.city and mine control survey etc.) starating from the fundamental formulae of Gauss comformal projection,therefore,the transformation relation between satellite and terrestrial networks is established to provide a necessary mathematical relation for the combined adjustment of satellite and terretrial networks in Gauss planimetric coordinate system.