For random noise presenting in phase-sensitive optical time domain reflectometer (Φ-OTDR) signals, a disturbance localization method based on differential Savitzky-Golay non-local means (SG-NLM) algorithm was proposed to reduce the noise in non-disturbed areas. The differential Savitzky-Golay (SG) smoothing filtering was used to achieve the preliminary localization of external disturbances. The Φ-OTDR amplitude signal noise could be further reduced by using the non-local means (NLM) algorithm, which was suitable for dealing with random noise included in two-dimensional signals. The experimental results show that the proposed method can maximally filter out random noise and achieve better localization effect. Compared with the traditional NLM algorithm and the amplitude variance localization method, the signal-to-noise ratio (SNR) is increased by 15.14 dB, and the spatial resolution is improved by 4.05 m.