The invention relates to an analog signal self-adaptive demodulation system and its implementation method, comprising a front panel, a signal processing board, and a receiver. The chip and the crystal oscillator are connected to the FPGA in one direction, the ARM processor and the network port chip are connected to the interface MCU in two directions, the interface MCU is connected to the FPGA in two directions, the input filter is connected to the ADC in one direction, and the ADC is connected to the FPGA in two directions. The panel is bidirectionally connected to the interface MCU, the signal source is bidirectionally connected to the network port chip, and the receiver is unidirectionally connected to the input filter. The demodulation module performs orthogonal decomposition on the sampling signal, and the sine and cosine signals generated by the numerical control oscillator are respectively multiplied by the sampling signal to obtain I The quadrature signal of channel Q and channel Q are filtered out by low-pass filter to remove high-frequency components, and then extract and reduce the speed to demodulate the modulated signal, and the result is output through the standard interface to realize automatic identification of signal modulation style and carrier synchronization , bit synchronization, frame synchronization.