The invention relates to a method for quickly positioning a phase-sensitive optical time-domain reflection distributed optical fiber sensing system. The method comprises the following steps of: constructing a Rayleigh scattering light digital signal matrix corresponding to a plurality of optical pulses; selecting test windows and test columns on the signal matrix at certain intervals; acquiring the phases of respective test columns; roughly positioning a disturbance source section according to adjacent test windows test column phase; and extracting a section signal (between two adjacent test window test columns) including the disturbance source for accurate disturbance positioning. The method analyzes the phase relation of the Rayleigh scattering light at different positions of an optical fiber to realize a rough positioning-precise positioning process of a [phi]-OTDR optical fiber sensing system, reduces the burden of the system by neglecting a large amount of invalid sensing information, solves poor real-time performance in the distributed sensing system caused by a large signal data size and a large system calculation magnitude, and is suitable for various coherent detection demodulation [phi]-OTDR system.