The utility model discloses a submarine cable vibrates monitoring devices, end device before vibration detection, submarine cable vibration monitoring processing center and user side, vibration detection before the superfluous afterglow more than among the submarine cable composite optical fiber of end device and extraction is fine links to each other as vibration monitoring distributed sensor, vibration detection before end device and submarine cable vibration detection processing center and user side distinguish the communication and be connected. The utility model discloses directly utilizing the fine conduct sensing fiber of superfluous afterglow among the composite cable of seabed, making its effect of having actd as vibration monitoring distributed sensor promptly, act as monitor information transmission medium again, need not to lay dedicated sensing and signal transmission optic fibre, monitoring technology implements conveniently, and investment province takes effect soon.