A new intermediate frequency digital demodulating method is proposed based on orthogonal device and feed-forward implementation, which can be easily implemented on universal communication system. The main algorithm of this demodulating method, including frequency offset estimation algorithm and timing recovery algorithm, is also discussed in detail. The mean square error (MSE) performances of these two main algorithms and of the bit error ratio (BER) of this demodulating method are simulated. The computer simulation result demonstrates the validity of this new intermediate frequency digital demodulating method.