The pressure drop at in and out ports of the magnetorheological valve (MRV) varies little as the resistance gap is not changed, and the MRV spool and the MRV body of a traditional MRV is relatively fixed. On basis of it, a novel MRV with a tunable resistance gap was proposed. The size of the resistance gap of flow pass in this MRV was tunable mechanically ranging from 10 mm to 20 mm. At the same time, a MRV test rig was built up, and experimental tests were carried out on related performance. The relationships among the pressure drop at in and out ports of the MRV, width of resistance gap, applied current and loading cases were analyzed concretely. Experimental results are contrasted for several times, which verify the stability of the proposed MRV.