Abstract: In order to calculate the sound power levels and the contributions radiated by the primary noise sources accurately when conducting noise source identification based on the microphones array and beamforming algorithm,the sound intensity scaling method was given out.The curves of error between the theoretical sound power level and the one calculated based on the scaled beamforming sound intensity for a single monopole indicate that the maximum error is just a little more than 0.1 dB when the distance from the sound source calculation plane to the array plane equals to the array diameter.Further,the method of integration in the partial area of the source calculation plane restricted by a certain dynamics range was given with the intention to avoid the interference from the sidelobes.The partial area sound power of a single monopole was simulated.The results show that the level integrated in the area restricted by a certain dynamics range approximates the level integrated in the mainlobe area and both of them equal to the theoretical sound power level approximately.Finally,the contrast experiment between the sound intensity method and the beamforming method validated the correctness and effectiveness of the partial area sound power calculation based on the scaled beamforming sound intensity.