Single-ended structure dynamic measuring Brillouin optical fiber sensing system and sensing method

The invention discloses a single-ended structure dynamic measuring Brillouin optical fiber sensing system and a sensing method. A sensing system laser light source outputs two continuous lights through a first coupler, the first continuous light enters the input end of a modulation high-extinction-ratio module, the modulation high-extinction-ratio module is connected to one input end of a second coupler; the second continuous light enters a phase shift modulating module, the phase shift modulating module is connected to the other input end of the second coupler; the second coupler is connected to the port I of an optical circulator, the port II of the optical circulator is connected with a single-ended module by the sensing optical fiber, the port III of the optical circulator is connected with a de-modulating module. By utilizing the single-ended structure, the BOTDA (Brillouin optical time domain analysis) nominal measuring distance is the effective measuring distance, the problems that the double-ended access is required in the actual measurement and the effective sensing distance is a half of the nominal sensing length existing in the prior art are solved; the extinction ratio of electro-optical modulator is improved, the measuring time is shortened, the monitoring functions of dynamic measurement and long-distance dynamic stress are realized.