This paper proposes a method for locating distributed fiber vibration intrusion events using Rayleigh backscattering (RBS) response section boundary combined with air-frequency energy distribution, aiming to address the issue of limited spatial resolution in traditional pipeline leakage monitoring systems due to the width of the detection pulse. The spatial frequency energy distribution is used to display the left boundary of the RBS response section to characterize the exact location of vibration intrusion events. Vibration detection experiments were carried out on the designed phase-sensitive optical time-domain reflectometer (φ-OTDR) with different width detection pulses, and the characteristics of RBS response section varying with the width of detection pulses were studied. Then, through vibration tests in three different environments, the feasibility and superiority of vibration location by combining air-frequency energy and RBS response section boundary are verified. The experiments show that the location accuracy of the system is 2 m when the sampling rate is 50 MS/s.