Phase　generated　carrier　(PGC)　homodyne　demodulation　technique　is　frequently　used　in　optical　fiber　interferometric　sensors　for　demodulating　sensing　signals.　However,　it　is　difficult　for　the　system　to　achieve　optimum　performance　because　the　electronic　components　which　constitute　the　analog　circuit　of　a　PGC　homodyne　demodulation　system　have　some　problems　such　as　overload,　improper　resistance,　etc.　all　those　will　bring　noise　to　the　system.　Therefore,　the　system　could　not　be　allowed　to　work　well　for　those　noises　introduced　by　electronic　components.　For　overcoming　these　disadvantages　of　the　analog　circuit　mentioned　above,　a　digital　PGC　demodulation　system　based　on　LabVIEW　is　described　in　this　paper,　and　it　is　applied　to　demodulate　the　sensing　signals　from　all　fiber　oil　pipeline　leakage　detection　system　based　on　Sagnac　interferometer.　The　results　verify　that　this　system　can　well　demodulate　sensing　signals.