The invention discloses a broadband chaotic laser-based distributed optical fiber dynamic strain sensing device, which comprises a broadband chaotic laser source (1), a 1*2 optical fiber coupler (2),a first polarization controller (3), a high-speed electro-optic modulator (4), a programmable optical delay generator (5), a first optical amplifier (6), an optical polarizer (7), an optical isolator(8), a sensing optical fiber (9), an optical circulator (10), a second optical amplifier (11), a semiconductor optical amplifier (12), a second polarization controller (13), a pulse signal generator (14), a broadband microwave signal source (15), a high speed data acquisition and analysis system (16), a photoelectric detector (17), and a tunable optical filter (18). The pulse signal generator is used to generate high speed pulse signals, synchronous control on the broadband microwave signal source, the semiconductor optical amplifier and the high speed data acquisition and analysis system is realized, and the measurement accuracy and the real-time performance of the sensing system are ensured.