Abstract: This paper is a report of the study on the combined adjustment of satellite and terrestrial network,which is a research project undertaken in recent years.In this paper the following points have been discussed:——the WUS model with seven parameters and model appending VLBI observations.(the former likely makes the deviation of the translation parameters minimum and the latter will be able to keep the scale parameter of the terrestrial network separate from the scale parameter of the satellite network).——the method of the combined adjustment by means of least squares collocation and build-up of observation equations in different coordinate system.——The analyses of the errors in the combined adjustment in which emphasis is placed on the concept of "Influence rate".——A development of the combined adjustment program with multifunction such as the location of the gross errors,estimation of the variance components;the hypothetic test of the transformation parameters and automatic selection of models with appropriate nember of transformation parameters and so on.——The application of the combined adjustment to North-West satellite network and terrestrial network.