Abstract: In this paper the difference between the origin of the reference geodetic system determined by Bursa model and that of the reference coordinate system determined by Molodenskii or Veis model in the adjustment for the combination of satellite and terrestrial networks is explained in geometric sense.And the three"transformation matrices" between transformation paraments which are respectively determined by the above three models are derived,and they are shown to be regular.Therefore the equivalence of the above three models in combining adjustment used for the determination of the transformation paraments is proved.Finally,it is pointed out that although an illconditioned design matrix may be contained in Bursa model,the difference in condition of design matrices of the above three modus have on effect on the final results and accuracy of the combining adjustment and the transformation from one to another coordinate system.