Abstract: In this paper, a sound field reconstructing method of spatial point source is introduced to the calibration of microphone array. Based on this method, a set of spatial point source reconstruction system is designed, and the positioning accuracy calibration of a microphone array is completed. In this paper, the spatial sound field synthesis algorithm of multi-channel sound sources is used to simulate a point source in a free spatial sound field. According to the spatial coordinates of each microphone in the microphone array, the dynamic acoustic signal of the sound field at the microphone's position is calculated. The coupling cavity standard sound source inputs the corresponding multi-channel voltage signals into the calibrated microphone array system to simulate point sound sources. By comparing the position of the simulated point source with that obtained by beamforming of the microphone array, the accuracy of microphone array positioning can be calibrated.