The invention discloses a stroke varying type double-cylinder active magneto-rheological shock absorber based on a shearing mode. The stroke varying type double-cylinder active magneto-rheological shock absorber based on the shearing mode is composed of a bottom cover, an outer cylinder barrel, an inner cylinder barrel, an electromagnetic valve, a piston rod, a floating piston, a piston surroundedby a coil, metal rubber, a fuzzy controller, a sensor and the like, the electromagnetic piston is located in the inner cylinder barrel, the piston rod is connected with the electromagnetic piston, the inner cylinder barrel and the outer cylinder barrel are fixed on the same base, the inner cylinder barrel and the outer cylinder barrel are connected through a through hole in the side wall of the inner cylinder barrel, the electromagnetic valve is arranged on the portion, corresponding to the through hole of the side wall of the inner cylinder barrel, of the side wall of the outer cylinder barrel, the metal rubber and the floating piston structure are arranged on the inner side of the outer cylinder barrel. When the vibration absorber works, a central controller of a vibration damping system can control the current on the electromagnetic coil and opening of the electromagnetic valve so as to control the output force of the shock absorber according to an acceleration signal transmitted by an acceleration sensor installed on the shock absorber; and the central control system of the shock absorber can control the opening and closing degree of the electromagnetic valve according to thesize of the road excitation, and the buffer stroke is controlled.