An optical signal transmission method includes: obtaining a signal identifier of data to be sent; obtaining corresponding optical frequency slot distribution information according to the signal identifier; and determining a corresponding carrier according to the obtained optical frequency slot distribution information, using the determined carrier to carry the data to be sent to generate an optical signal, and sending the generated optical signal. The optical signal transmission method provided in the present invention does not fix the optical frequency slot distribution into a wavelength identifier, the number of optical frequency slots is not limited by the wavelength identifier field length, and the data to be sent can be transmitted in an optical network by being carried on the carrier determined according to multiple optical frequency slots.