An optical signal transceiver apparatus, wherein the apparatus comprises: an optical signal generation module, an optical combining/splitting module, a coherent receiving module, and a signal processing module, wherein the optical signal generation module is configured to: generate a to-be-sent optical signal and a local oscillator optical signal, wherein the to-be-sent optical signal comprises a first optical time domain reflectometer, OTDR, signal; input the local oscillator optical signal into the coherent receiving module; and input the to-be-sent optical signal into an optical fiber by using the optical combining/splitting module; the optical combining/splitting module is configured to: receive a to-be-processed optical signal from the optical fiber; and input the to-be-processed optical signal into the coherent receiving module, wherein the to-be-processed optical signal comprises at a same time a first optical supervisory channel, OSC, signal and a second OTDR signal that is obtained by the optical fiber by reflecting and/or scattering the first OTDR signal, a frequency of the first OSC signal is different from a frequency of the second OTDR signal, and a difference between the frequency of the first OSC signal and the frequency of the second OTDR signal is less than a processing bandwidth of the coherent receiving module, the processing bandwidth of the coherent receiving module being a signal bandwidth that can be processed by the coherent receiving module; the coherent receiving module is configured to: coherently receive the local oscillator optical signal and the to-be-processed optical signal to obtain a to-be-processed electrical signal; and send the to-be-processed electrical signal to the signal processing module; and the signal processing module is configured to: obtain, from the to-be-processed electrical signal based on a signal frequency, a first digital signal corresponding to the first OSC signal and a second digital signal corresponding to the second OTDR signal; process the first digital signal to obtain a communications code stream; and process the second digital signal to obtain information used to reflect a feature of the optical fiber; and the optical signal transceiver apparatus further comprises a frequency control module, wherein the signal processing module is further configured to: obtain a frequency offset of the first OSC signal relative to the local oscillator optical signal; and control, based on the frequency offset by using the frequency control module, a difference between a frequency of the first OTDR signal generated by the optical signal generation module and the frequency of the first OSC signal to be equal to a preset difference. an optical signal generation module, an optical combining/splitting module, a coherent receiving module, and a signal processing module, wherein the optical signal generation module is configured to: generate a to-be-sent optical signal and a local oscillator optical signal, wherein the to-be-sent optical signal comprises a first optical time domain reflectometer, OTDR, signal; input the local oscillator optical signal into the coherent receiving module; and input the to-be-sent optical signal into an optical fiber by using the optical combining/splitting module; the optical combining/splitting module is configured to: receive a to-be-processed optical signal from the optical fiber; and input the to-be-processed optical signal into the coherent receiving module, wherein the to-be-processed optical signal comprises at a same time a first optical supervisory channel, OSC, signal and a second OTDR signal that is obtained by the optical fiber by reflecting and/or scattering the first OTDR signal, a frequency of the first OSC signal is different from a frequency of the second OTDR signal, and a difference between the frequency of the first OSC signal and the frequency of the second OTDR signal is less than a processing bandwidth of the coherent receiving module, the processing bandwidth of the coherent receiving module being a signal bandwidth that can be processed by the coherent receiving module; the coherent receiving module is configured to: coherently receive the local oscillator optical signal and the to-be-processed optical signal to obtain a to-be-processed electrical signal; and send the to-be-processed electrical signal to the signal processing module; and the signal processing module is configured to: obtain, from the to-be-processed electrical signal based on a signal frequency, a first digital signal corresponding to the first OSC signal and a second digital signal corresponding to the second OTDR signal; process the first digital signal to obtain a communications code stream; and process the second digital signal to obtain information used to reflect a feature of the optical fiber; and the optical signal transceiver apparatus further comprises a frequency control module, wherein the signal processing module is further configured to: obtain a frequency offset of the first OSC signal relative to the local oscillator optical signal; and control, based on the frequency offset by using the frequency control module, a difference between a frequency of the first OTDR signal generated by the optical signal generation module and the frequency of the first OSC signal to be equal to a preset difference.