A flexible circuit board, and an optical transceiver assembly and an optical module that have such flexible circuit board. The flexible circuit board includes a substrate body, a transmission metal layer formed on at least one surface of the substrate body, a strengthening layer formed on the transmission metal layer, and a surface metal layer formed on a portion of an outer surface of the strengthening layer. The surface metal layer constitutes a securing portion for securing and connecting to an external element. A portion of the flexible circuit board that is not covered by the surface metal layer constitutes a connecting portion that connects to the securing portion. The surface metal layer is electrically connected to the transmission metal layer.