Abstract Aiming at selection of frame sites, combination of global Hfiles and selection of parameters of similarity transformation, four calculation schemes are designed to process the observations of regional GNSS net in large, medium and small scale . On the basis of these solutions, the differences shown as follows between results under different calculation schemes are analyzed. As far as all levels of regional net are concerned, if combined with global Hfiles and similarity transformation is invoked successfully, the difference between the results under scheme which selects whole frame sites of IGS05 and which selects a part uniformly is not significant. For large regional GNSS net, the scheme combined with global Hfiles gets different result from the scheme which doesn’t be combine, with a maximum up to 4 mm/a in the horizontal velocity of ITRF2005. As for medium and small regional GNSS net, the difference of relative velocity field between the results of scheme which combines with global Hfiles and which not is in significant.
