In response to the large amount of data processing in phase-sensitive optical time-domain reflection (Φ-OTDR) technology for disturbance localization, a positioning method combining region segmentation and edge detection is proposed. The fast coarse localization of the disturbance occurrence region is achieved by dividing the optical fiber into segments, followed by fine localization using an edge detection algorithm based on the Sobel operator within the disturbance region. A heterodyne coherent Φ-OTDR system is employed for data acquisition in the experiments to localize three types of disturbance events on a 5 km sensing fiber. The results show that the coarse positioning method based on region segmentation enhances the system's ability to locate disturbances in noise. The average processing time for each sample is only 0.046 s, which is an order of magnitude lower than that of the traditional method. In addition, the proposed combined method improves real-time localization over using edge detection algorithm alone, while maintaining localization accuracy. The localization error is less than 2.84 m, indicating potential for application in accurately locating external disturbances in real-time systems.