Abstract: In this paper, the practical method for determining the rheological parameters s and r of an astatic gravimeter is given. For the first time, the authors obtained the numerical values of these two parameters, that is =0.010 and =795.8 minutes for the gravimeter CG-2 No. 317, based on the precise observational results of earth tides at the Wuhan station, during the China-Belgium Cooperation period. The work indicates that the method is valid for determining the rheological model of an astatic gravimeter.