The invention relates to a decoding method and a decoding device. The decodes a coded picture signal, including: using reference pictures and an instruction capable of distributing a plurality of reference indices to at least a reference picture to determine a corresponding relation of each reference index and each reference picture; using a first weighting coefficient set corresponding to one intwo reference indices and a pixel value of a first reference block to generate a predictive pixel value of a first decoding block; using a second weighting coefficient set corresponding to another one in two reference indices and the pixel value of a second reference block to generate the predictive pixel value of a second decoding block and generate the predictive picture of the predictive pixelvalue of the decoded picture; and using the predictive pixel value of the generated decoded picture to decode the decoded picture.