The invention relates to a distributed optical fiber sensing system, and in particular relates to a chaos Brillouin optical coherence domain analysis distributed optical fiber sensing device and method. According to the invention, the problems of unavailable spatial resolution and sensing distance combination, severely limited sensing distance and low spatial resolution of the existing distributed optical fiber sensing system are solved. The chaos Brillouin optical coherence domain analysis distributed optical fiber sensing device comprises a wide spectrum chaos semiconductor laser, a 1*2 optical fiber coupler, an optical scrambler, an optical isolator, a first optical amplifier, a variable optical delay line, a second optical amplifier, an optical circulator, a sensing optical fiber, a tunable optical filter, a broadband gain photodetector, a data acquisition device, a signal processing device and a display device. The device and the method, which are provided by the invention, are applicable to the field of distributed optical fiber sensing.