The invention discloses a weighted soft decoding method based on a single-carrier frequency-division multiple access system and solves the problem that in the prior art, a weighted decoding method islow in channel frequency selective fading resistance, is low in to-be-decoded soft information signal to noise ratio and is high in algorithm complexity. The realization method of the method comprisesthe steps of generating coded and modulated data; acquiring frequency domain data; generating mapped frequency domain data; acquiring time frequency sending signals; acquiring received time domain signals; acquiring received frequency domain signals; acquiring subcarrier de-mapped signals; carrying out channel balancing; acquiring a weighting factor; weighing balanced signals; carrying out demodulation and soft-decision; and carrying out soft decoding. The method has the advantages of high soft information signal to noise ratio, high channel frequency selective fading resistance, low algorithm complexity and simple realization. According to the method, the decoding performance is improved well finally.