The invention discloses a zero gravity suspension test device for a cylindrical surface expansion mechanism. The test device comprises a support assembly, a suspension guide rail assembly and a guiderail auxiliary moving assembly. The support assembly is used for fixing and supporting a cylindrical surface expansion mechanism, the suspension guide rail assembly comprises a fixed guide rail and atranslational guide rail, slide blocks capable of moving along the guide rails are arranged on the guide rails, one end of a suspension rope is connected with the expansion mechanism while the other end is connected with a counterweight after running through a pulley wheel, effects exerted on expansion processes by the expansion mechanism can be eliminated via the counterweight, the guide rail auxiliary moving assembly comprises an electric motor and a leading screw slide platform, the leading screw slide platform is enabled to move under drive of the electric motor, the translational guide rail in the suspension guide rail assembly is further driven to move, and the translational guide rail can be enabled to be positioned right above a suspension rope and a suspension ring of the expansion mechanism all along during the expansion processes. Via the zero gravity suspension test device, gravity discharging operation can be effectively performed during the expansion processes of the cylindrical surface expansion mechanism, and the zero gravity suspension test device is simple in structure and can be applied to ground surface zero gravity expansion tests of cylindrical surface expansion mechanism.