The invention provides a method for labeling an optical fiber wavelength, including: deploying a spreading code on each of a transmit end and a receive end; transmitting a message code, and spreading the message code by using the spreading code of the transmit end; and performing envelope modulation on an optical signal by using the spread message code, transmitting the optical signal after the envelope modulation to the receive end, choosing, the spreading code of the receive end to despread the message code to obtain the original message code of the transmit end, and obtaining a corresponding wavelength according to the spreading code of the receive end. A spreading code having a correspondence with a wavelength is used to spread and despread a message code, and a modulation depth of an amplitude modulated signal may be greatly reduced to nearly prevent an envelope modulated signal from affecting a main signal.