A method of improving measurement speed of distributed optical fiber sensors by adopting orthogonal signals and the system thereof is disclosed, which is related to the optical fiber sensor field and solves the problems that conventional technology will increasing the bandwidth of the received signal, reducing the signal-to-noise ratio of the received signal or distortion the spatial resolution of the system. The method comprises steps of generating N periodic orthogonal optical pulse sequence; injecting the N periodic orthogonal optical pulse sequence into the optical fiber under test(5); collecting the scattered light signal; demodulating the scattered light signal with the local oscillating light and then converting into digital signals; extracting the scatter information of the orthogonal optical pulses from the collected digital signals; and arranging the scattered information in order of precedence of the infusion. The measurement speed of the distributed optical fiber sensors is improved by N−1 times.