The invention discloses a variable damper magnetic circuit structure which comprises a piston cylinder. A piston rod is arranged in the piston cylinder; a piston sleeves outside the piston rod and tightly contacts an inner wall of the piston cylinder; a horizontal partition is arranged in the middle of the piston; sinking parts are arranged on the upper side and the lower side of the horizontal partition; the horizontal partition divides the piston in to an upper part and a lower part; a first coil winds on the upper part; a second coil winds on the lower part; the first coil and the second coil are connected with an inverse current; and a magnetorheological fluid is filled in the piston cylinder. According to the variable damper magnetic circuit structure provided by the invention, multiple magnet exciting coils wind on the piston, so that the magnitude of the magnetic flux can be increased, the effective length of the piston can be further increased, and a magnetic circuit becomes more uniform; during a codirectional current and the inverse current of the two-stage coil, the magnetic field utilization ratio is the highest, and a damping force can be remarkably improved.