The　non-contact　detection　of　buried　ferromagnetic　pipeline　is　a　long-standing　problem　in　the　field　of　inspection　of　outside　pipelines,　and　the　extraction　of　magnetic　anomaly　signal　is　a　prerequisite　for　accurate　detection.　Pipeline　defects　can　cause　the　fluctuation　of　magnetic　signals,　which　are　easily　submerged　in　wide-band　background　noise　without　external　excitation　sources.　Previously,　Variational　Mode　Decomposition　(VMD)　was　used　to　separate　modal　components;　however,　VMD　is　based　on　narrow-band　signal　processing　algorithm　and　the　calculation　is　complex.　In　this　article,　a　method　of　pipeline　defect　signal　based　on　Variational　Specific　Mode　Extraction　(VSME)　is　employed　to　extract　the　signal　of　a　specific　central　frequency　by　signal　modal　decomposition,　i.e.,　the　specific　mode　is　weak　magnetic　anomaly　signal　of　pipeline　defects.　VSME　is　based　on　the　fact　that　a　wide-band　signal　can　be　converted　into　a　narrow-band　signal　by　demodulation　method.　Furthermore,　the　problem　of　wide-band　signal　decomposition　is　expressed　as　an　optimal　demodulation　problem,　which　can　be　solved　by　alternating　direction　method　of　multipliers.　The　proposed　algorithm　is　verified　by　artificially　synthesized　signals,　and　its　performance　is　better　than　that　of　VMD.　The　results　showed　that　the　VSME　method　can　extract　the　magnetic　anomaly　signal　of　pipeline　damage　using　experimental　data,　while　obtaining　a　better　accuracy.　©　2020　by　the　authors.