This paper mainly investigates the shear performance of a metal foam magnetorheological (MR) fluid damper. As for the damper, MR fluids are stored in metal foam in the action of magnetic field, MR fluids are drawn out from the metal foam, and then fill the shear gap, thus producing the MR effect. Based on previous research, as a sample, the metal foam nickel (Ni) is applied to store MR fluids, and the metal foam Ni MR fluid damper is designed and manufactured. A test rig, including the metal foam MR fluid damper, dc motor with speed controller, force sensor with amplifier, and DAQ card and PC with LabVIEW software, is built to study the shear performance. The effects of excitation current and shear rate on damping force are analyzed. Besides, considering the influence of different currents on magnetic field, a series of magnetic field simulations on the damper are carried out in ANSYS FEM software. The results show that the excitation current is the key factor to damping force of the damper; with the increasing of the current, the damping force will increase. However, once the current is above 1.5 A, the increment is no longer obvious. Besides, damping force will decrease with the share rate increasing.