Geographical Survey Institute (GSI) continues periodical domestic VLBI experiments and daily GPS measurements. By these space geodetic technologies, Japan Geodetic Datum 2000 has been constructed and will be introduced in AD 2000. The Japanese Islands are on more than four plates, so the crustal movements are very complex and it causes rapid deformation in the geodetic reference frame. GSI keeps the crustal movements under observation to mainten the JGD2000. Five VLBI stations and 959 GPS stations give us quite detailed information on continuous crustal movements. In the space geodetic period, it is difficult to keep a fixed geodetic reference frame because a non-special GPS survey can easily detect a small shift between a local geodetic reference frame and global reference frame. We have compared the results of the periodical VLBI experiments with daily GPS measurements. Two observations look very good to harmonize. We have estimated the velocities of the crustal movements and discussed the effect on maintenance of the JGD2000.