This paper reports that polycrystalline Si 0.956 Mn 0.044 :B films have been prepared by cosputtering deposition followed by rapid thermal annealing for crystallization. The polycrystalline thin films were treated by hydrogen plasma excited with approach of radio-frequency plasma enhanced chemical vapour deposition for different time of 10 minutes, 15 minutes and 40 minutes. After hydrogenation, the structural properties of the films do not show any change, while both the saturation magnetization and the hole concentration in the films increase at first, then decrease with the increase of hydrogenation time. The obvious correlation between the magnetic properties and the transport properties of the polycrystalline Si 0.956 Mn 0.044 :B films suggests that a mechanism of hole-mediated ferromagnetism is believed to exist in Si-based diluted magnetic semiconductors. This paper reports that polycrystalline Si 0.956 Mn 0.044: B films have been prepared by cosputtering deposition followed by rapid thermal annealing for crystallization. The polycrystalline thin films were treated by hydrogen plasma excited with approach of radio-frequency plasma enhanced chemical vapor deposition for different time After hydrogenation, the structural properties of the films do not show any change, while both the saturation magnetization and the hole concentrations in the films increase at first then decrease with the increase of hydrogenation time. The obvious correlation between the magnetic properties and the transport properties of the polycrystalline Si 0.956 Mn 0.044: B films suggests that a mechanism of hole-mediated ferromagnetism is believed to exist in Si-based diluted magnetic semiconductors.