In order to improve the HV hardness and microstructure on the surface of TC4 titanium alloy, the high frequency scan of electron beam had been introduced to treat TC4 titanium alloy. For acquiring excellent parameters, the energy of EB, focus current and scan times, which will influence the HV hardness and microstructres, had been studied respectively. After high frequency scan of electron beam treatment, the HV hardness, modified layer depth and microstructures of TC4 titanium alloy had been analyzed respectively. It is shown that the HV hardness on the TC4 surface treated by the high frequency scan of electron beam can be increased almost 40Mpa than original material. With energy of EB improved, the depth layer influenced is increased. The focus current adjusted at little range can acquire comparatively better HV hardness on the surface. When the scan times are increased, not only the HV hardness decreases, but also the grains grow up.