The invention discloses an anti-precipitation magnetorheological fluid damper. The inner side of a bottom end cover is connected with one side of an anti-precipitation valve through a flat end surfacespring; an aluminum magnet sleeve is arranged on the other side of the anti-precipitation sleeve; a magnet is embedded in the aluminum magnet sleeve; a cylinder wall between the anti-precipitation valve and an upper end cover is fully filled with magnetorheological fluid; one end of a guide rod for a piston penetrates through the upper end cover; multiple sets of pistons are arranged at the otherend of the guide rod for the piston; permanent magnet tiles are arranged among the pistons, and are wound with coils; aluminum magnet sleeves are arranged on the surfaces of the pistons correspondingto the anti-precipitation sleeve; magnets are embedded in the aluminum magnet sleeves; and guide magnetic separation aluminum sheets are arranged in the connecting places of the guide rod for the piston and the pistons. The anti-precipitation magnetorheological fluid damper has the following advantages: as repulsive permanent magnets are properly distributed between the anti-precipitation valve and the bottom surfaces of the pistons to form repulsive magnetic fields, magnetic particles in magnetorheological suspension are distributed according to magnetic lines of force due to acception of more stable magnetic force, and no precipitation is generated.