A Cable Television optical fiber communication system is disclosed, comprises a provider end, plural optical signal transmission devices and plural user ends, each optical signal transmission device is provided between the provider end and the user ends and has an light splitting element, a RF receive module, and a RF return module. The light splitting element is connected to the provider end via an optical transmission wire and is served to bi-directionally transfer a laser beam having a signal between the provider end and the user ends. The RF receive module is served to transfer a first signal of the provider end to the user ends. The RF return module emits a laser beam having a second signal to the provider end only when an analog return signal is emitted from the user end.