The invention provides sound detection equipment based on the laser device diffraction principle. The sound detection equipment is used for detecting sound made by a sound source and comprises a first infrared laser device, a second laser device, an electronic control slit, a photoelectric detection device, a signal processing device, a receiving screen, a brightness collection module and a sound restoration device. According to the sound detection equipment, the first infrared laser device is used for irradiating objects capable of vibrating near the sound source; the photoelectric detection device is used for receiving reflected infrared lasers; the electronic control slit is used for stimulating the change of the irradiation position of the reflected infrared lasers on the photoelectric detection device; the second laser device is used for irradiating the electronic control slit, and then the width of the slit and vibration of the objects capable of vibrating are determined based on the light intensity of diffraction striations. By the adoption of the sound detection equipment, the detection of the photoelectric detection device for the laser position is converted into the detection for the distance between two baffles of the electronic control slit, detection is more accurate, and the influence of noise on the sound detection equipment is smaller.