A method is provided for digital Simultaneous Information and Energy Transfer (SIET), comprising the steps of receiving a serial SIET analog signal, and converting the serial SIET analog signal received into a parallel SIET analog signal, extracting an analog information signal and an analog energy signal from the parallel SIET analog signal, performing analog-to-digital conversion on the analog information signal to obtain a digital information signal, and performing information demodulation, parallel-to-serial conversion and decoding on the digital information signal in digital domain, and pre-processing the analog energy signal in analog domain and storing the preprocessed analog energy signal. As the information signal is processed in the digital domain and the energy signal is processed in the analog domain, the energy in the SIET signal can be full collected in receiving side.