The　optimum　pretreatment　process　is　especially　required　in　order　to　get　the　exact　concentration　of　PCBs　in　municipal　sewage.　In　the　paper,　C18　solid-phase　extraction　(SPE)　columns　were　adopted　in　the　enriching　of　PCBs　in　Harbin　municipal　sewage,　and　the　target　compounds　were　extracted　with　mixed　extractant　of　acetone　and　n-hexane　of　1:1　in　the　optimum　dosage　of　10　milliliter.　And　the　extract　was　further　purified　with　sulfuric　acid,　silica　gel　and　anhydrous　sodium　sulfate.　GC-MS　was　applied　in　the　identification　and　quantification　of　PCBs　in　sewage　samples,　and　seven　PCBs　congeners　recommended　by　EPA　were　chosen　as　the　exterior　references.　It　indicated　that　the　total　concentration　of　the　seven　PCBs　in　the　sewage　samples　was　27.75　ng/L,　the　relative　standard　deviations　of　the　method　were　in　the　scope　of　1.6%-8.8%,　the　recoveries　were　between　84%　and　103%,　and　the　lowest　detection　limit　of　PCBs　was　0.014　μg/L.