The invention relates to a single-fiber bidirectional time-division multiplexing light amplification apparatus in a fiber time frequency transmission field. The single-fiber bidirectional time-division multiplexing light amplification apparatus comprises a first optical splitter, a first magneto-optical switch, a single-fiber bidirectional optical amplifier without an isolator, a second magneto-optical switch, a second optical splitter and a control unit. On the basis of a relationship between a light passing direction of a magneto-optical switch and a control voltage, light passing directions of the magneto-optical switches are controlled according to a detected optical signal transmission direction and thus optical signals in forward transmission and backward transmission on a time transfer channel enter the single-fiber bidirectional optical amplifier at different time, so that same-fiber same-wave bidirectional amplification of optical signals with timing signals in a BTDM-SFSW time transfer link is realized and the link symmetry is guaranteed to the greatest extent. With unidirectional light passing characteristic of the magneto-optical switch, the influence on a fiber time transfer performance by multiple times of amplification of the noise like rayleigh scattering can be avoided effectively.