The work aims to obtain medical titanium alloy with super smooth surface and non-toxic residue. Medical titanium alloy was polished by cluster Magnetorheological finishing (CMRF) with dynamic magnetic fields, a new method of semi-fixed abrasive polishing. The influence of abrasive type, abrasive size, polishing time, machining gap and polishing plate speed on surface morphology and surface roughness of medical titanium alloy was studied. The surface of medical titanium alloy before and after polishing was element analyzed by scanning electron microscope. The surface morphology of titanium alloy was influenced by the shape and hardness of abrasive. Al2O3 abrasive can obtain higher surface quality than SiC, SiO2 and B4C. When the sizes of Al2O3 abrasive increases, the surface roughness first decreases and then increases, among which 5 μm Al2O3 has the best polishing effect. When the machining gap increased from 0.8 mm to 1.2 mm, the surface roughness first decreased and then increased. And the processing effect was the best at 1 mm. When the rotation speed of the polishing plate increases from 15 r/min to 35 r/min, The surface roughness first decreases and then increases, among which 25 r/min has the optimal processing effect. In the 1 mm machining gap, medical titanium alloy was polished with the Al2O3 abrasive of 5 μm and the polishing plate rotation speed of 25 r/min for 4 h, the surface roughness decreased from the original Ra 110 nm to Ra 2.87 nm and the change rate of surface roughness was 97.39%. The super smooth surface without scratch of medical titanium alloy can be obtained by CMRF with dynamic magnetic fields.