Mark III VLBI observations between August 1979 and December 1998 were analyzed to yield the terrestrial and celestial reference frames (TRF and CRF) and the Earth Orientation Parameters (EOP). Comparisons with ITRF96, RSC (WGRF) 95 R01 and EOP (IERS) 97 C04 are performed. For CRF, the three orientation angles are not significant at the level of precision of 0.1 mas. Though no significant values are found for the three deformation parameters, coordinate drifts up to 0.5 mas are identifiable for

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... ome sources in the southern hemisphere. The relative rotation angles and their rates of change for TRF are not significant respectively at the precision level of 0.2 mas and 0.1 mas/yr. Detailed comparisons however show that the differences in the velocity field are obvious for the eastern part of Eurasian plate and Australian plate. About EOP series, the systematic differences and the relative drifts are not significant respectively at the level of 0.4 mas and 0.1 mas/yr.