The invention discloses a method for increasing the doping concentration of phosphor in a nanometer silicon material through employing the boron-phosphor codoping technology, and the method comprises the following steps: 1), preparing a multilayer film material doped with nanometer silicon/silicon oxide through employing PECVD; 2), obtaining the multilayer film material doped with nanometer silicon/silicon oxide (a-Si/SiO2) through the alternate conducting of two processes: noncrystalline silicon layer deposition/in-situ oxidation, and obtaining the thickness of the a-Si/SiO2 multilayer film through controlling the time of the noncrystalline silicon layer deposition/in-situ oxidation; 3), carrying out the dehydrogenation processing of the prepared a-Si/SiO2 multilayer film; 4), carrying out the high-temperature annealing under the nitrogen condition after dehydrogenation, enabling polycrystalline silicon to be crystalized to form nanometer silicon, activating foreign matter atoms to enter the nanometer silicon, and achieving the doping of the nanometer silicon. The method prepares the codoping nanometer silicon/silicon oxide multilayer film.