The invention discloses a micro-torque sensor calibrator based on a magnetic suspension effect. A microtorque sensor to be calibrated is fixed on a base by a positioning block and a clasping block; a moment arm with a circular arc side is installed on a rotating shaft; the bottom surface of the base is provided with a height adjusting support pin, and a guide column and a guide rail are installedon the height adjusting support pin; a bearing frame is installed on the guide rail, the edge of the bearing frame is slotted, and a micro-bearing is installed in a groove; a lead penetrates through the groove on the bearing frame and is hung on the micro-bearing, one end is fixed at the circular arc sides at both ends of the moment arm, and a weight is hung on the other end; a magnetic seat is installed on the guide column; and the central position of the moment arm and the central position of the magnetic seat are respectively provided with disk-shaped magnets. The invention can eliminate the bending moment applied to the rotating shaft of the microtorque sensor to be calibrated by moment arm weight during horizontal arrangement, realize pure torque loading, ensure that the torque is a constant value and meanwhile lead the moment arm to be in a suspension state, has the characteristics of simple structure, high precision and high stability and more favorably meets the calibrating requirement of the microtorque sensor.