A large-amplitude vibration active spacer bar consists of a rotor, a stator and a position sensor. When the large-amplitude vibration active spacer bar is in operation, the rotor is positioned at the upper part, the stator is positioned at the lower part and the rotor moves up and down relative to the stator so as to counteract the vibration transmitted from the stator and stabilize the rotor; the rotor consists of an internal support cylinder, a linear guide rail slide block, a linear guide rail and a motor rotor; the stator consists of a dustproof cover, a guide rail fixed plate, a motor stator, an external support cylinder, a positioning screw and a top positioning block; the position sensor consists of a grating fixed plate and a grating sensor. The large-amplitude vibration active spacer bar has the advantages of large stroke, large load capacity, quick response speed, high reliability, large vibration insulation amplitude, wide frequency band, etc.