A Brillouin correlation domain analysis system based on strength modulation belongs to the field of distributed fiber sensing technology. The system aims to settle a problem of low spatial resolutioncaused by incomplete phase modulating code type of an existing Brillouin correlation domain analysis method. Laser emitted from a laser device is modulated by a phase modulator for dividing into an upper path and a lower path. The upper path is used as detecting light and is modulated to down-frequency-shift detecting light by a single-sideband electro-optic modulator. The modulated detecting light enters a to-be-detected fiber through a first erbium doped fiber amplifier and a time delay fiber. The lower path is used as pumping light and enters a second erbium doped fiber amplifier. The lowerpath is input into a circulator and enters the to-be-detected fiber after outputting from the circulator. After the detecting light interacts with the pumping light in the to-be-detected fiber, the detecting light is input into the circulator. The detecting light is output from the circulator and enters a photoelectric detector. After an oscilloscope acquires the signal of the photoelectric detector, noise elimination and demodulation are realized through averaging, thereby obtaining the temperature and the strain information of the related peak in the to-be-detected fiber. The Brillouin correlation domain analysis system is used for seamless detection.