This invention discloses a suppression method for realizing fault lower stream alarm of fiber line, a quick resume method based on said method and an optical amplifier for realizing the alarm suppression and an optical communication system including: adjacent station points at both sides of the fault point keep the optical signal output to its own lower stream station points after testing fault offiber circuit and load ID signals carrying the alarm suppression information, after the lower stream station points receive the ID signals, they maintain the normal working state, after the fault istested and modified, the adjacent station points stop loading said ID signals to the lower points and resumes the normal working state and the lower stream station points continue the normal working state.