Aiming at solving the problems of complex wiring and high cost of the existing distributed light emitting diode (LED) dimming system, a new LED intelligent dimming system is proposed in this paper. Power/signal multiplexing modulation and transmission technology is applied to the LED drive circuits, and power and signal are simultaneously transmitted through the power bus. Quaternary differential phase shift keying (QDPSK) and orthogonal frequency division multiplexing (OFDM) are used to improve the communication efficiency. It realizes the communication between multiple LEDs for intelligent dimming control without additional hardware circuit, which greatly reduces the system volume, cost and complexity, enhancing the system reliability as well. Finally, the correctness and feasibility of the LED intelligent dimming strategy is verified by PSIM simulations.