B-doped Ti film is fabricated by direct current magnetron sputtering. The doping concentration, surface morphology, crystal structure, crystal grain diameter and stress are characterized by X-ray photoelectron spectroscopy, scanning electron microscopy and X-ray diffraction, respectively. It is found that, with the increase of B doping, the crystal grain diameter decreases monotonically and reaches a minimum of 1.3 nm at a B doping concentration of 5.50 at.%. The B-doped Ti film presents a compact columnar structure at that concentration. The stress of Ti film changes from compressive stress to tensile stress when B is doped.