The invention provides a variable magnetic buoyancy gravity compensator. The gravity compensator comprises an adjusting magnet, a central column magnet, an outer ring magnet, an outer ring magnet shell and an adjusting magnet vertical driving mechanism which are sequentially concentrically arranged from inside to outside, wherein the adjusting magnet is arranged in a central hole of the central column magnet, one end of the adjusting magnet is mounted on the adjusting magnet vertical driving mechanism, the magnetizing directions of the adjusting magnet and the central column magnet are opposite, and the adjusting magnet vertical driving mechanism is used for adjusting the adjusting magnet to move relative to the vertical direction of the central column magnet so as to adjust the magnetic buoyancy of the gravity compensator. By arranging the vertical adjusting magnet, a 50% wide-range non-polar adjustable magnetic levitation gravity compensation force can be provided without influencingthe horizontal stroke, so that the application range and flexibility of the gravity compensator are greatly improved.