The present application discloses an image coding/decoding method, device, and system, where an encoder performs singular vector decomposition on a prediction block corresponding to a to-be-coded image block, to obtain eigenvector matrices U and V of the prediction block; and performs coding processing on residual data according to the eigenvector matrices U and V of the prediction block, where the residual data is a difference between a pixel value of the to-be-coded image block and a pixel value of the corresponding prediction block. This can reduce identifier load of a coded bit stream.