In this paper， a chemical magnetorheological polishing method based on the Halbach magnetic field array is utilized to enhance the precision and efficiency of polishing medical titanium alloy （TC4）. Strengthening the magnetic field strength is used for the Halbach magnetic field array， and hydrogen peroxide solution is incorporated as an oxidant in the polishing process. Firstly， the Halbach magnetic field array is compared with the conventional N-S magnetic field array through simulation. Subsequently， the activity of carbonyl iron powder is adjusted to verify the experimental feasibility. The effects of working gap， main shaft speed， and abrasive particle size on surface roughness and contact angle of workpiece surface are then investigated. The results demonstrate that the Halbach magnetic field array exhibits higher magnetic-field strength than the conventional N-S magnetic field array. Moreover， the surface roughness of the medical titanium alloy polished using this method is 80% lower than that achieved through single pure magnetorheological polishing. Optimal smoothing of the workpiece surface is achieved at a working gap of 0.8 mm， a main shaft speed of 400 rad/min， and an abrasive particle size of 1 μm， resulting in an optimal Ra value of 15.5 nm. The surface contact angle measurements indicate that the majority of contact angle values for the titanium alloy surface in the experimental group are less than 90°. In conclusion， the application of this method for polishing medical titanium alloy yields an ultra-smooth surface and enhances its hydrophilicity， thereby meeting the standards required for medical titanium alloys.