The embodiment of the invention provides an optical fiber signal generation method, device and system. The method comprises the steps of obtaining a to-be-processed bit sequence; performing probability forming processing on the to-be-processed bit sequence according to a preset algorithm to obtain a probability forming sequence; mapping the probability shaping sequence to a preset constellation diagram to obtain a geometric-probability shaping signal, the preset constellation diagram being obtained by performing geometric shaping processing according to a mapping relationship between a presetnumber of codewords and probabilities, and the preset number of codewords being not completely the same in code length; and performing QAM processing on the geometric-probabilistic shaping signal to obtain an optical fiber signal. By applying the technical scheme provided by the embodiment of the invention, geometric forming and probability forming technologies are applied to QAM processing to obtain an optical fiber signal, the probability forming technology can improve the system capacity and reduce the sending power, and the geometric forming technology can improve the system bit error rateperformance, so that middle-distance and long-distance transmission of an optical fiber transmission system is realized.