An optical transceiver apparatus and an optical signal processing method. The optical transceiver apparatus may include a light source, an optical signal processor, and an optical path selector. The light source is separately connected to the optical signal processor and the optical path selector, and the optical signal processor is connected to the optical path selector. The light source is configured to provide a first local oscillator optical signal and a first carrier optical signal. The optical signal processor is configured to modulate the first carrier optical signal and output a first modulated optical signal. The optical path selector is configured to transmit the first local oscillator optical signal and the first modulated optical signal to the optical signal processor or a transmission fiber. Herein, the transmission fiber is configured to transmit an optical signal to an outside of the optical transceiver apparatus.