The invention provides a hung p-n junction quantum well-based photoinduced transistor and a preparation method thereof. A silicon substrate layer under a device structure is stripped and removed by an anisotropic silicon etching technique to obtain a hung nitride film p-n junction quantum well-based photoinduced transistor; and an ultra-thin hanging device is further obtained by a nitride behind-the-back thinning etching technology. According to the hung p-n junction quantum well-based photoinduced transistor, one end of the transistor is taken as an LED light source; and the other end is taken as a photoelectric detector. Due to excellent spectral matching characteristics between two devices, a photoelectric detector can sense a light emitted from an LED device; a photo-signal is converted into an electric signal for output; and the photoinduced transistor characteristics of the devices are achieved. The transistor independently transmits the modulated photo-signal as two common-ground LED light sources, so that two-channel emission of visible light wireless communication is achieved. The transistor can independently sense a spatial photo-signal as two common-ground photoelectric detectors, and achieves dual-channel detection of visible light wireless communication.