ρ(VFA)　is　a　key　factor　in　enhanced　biological　phosphorus　removal　process,　and　the　effect　of　biological　phosphorous　removal　can　be　improved　with　VFA　increased　in　influent.　The　effects　of　primary　sludge　fermentation　on　the(VFA),　ρ(C):　ρ(P)in　the　biochemistry　reaction　system　are　discussed　by　comparing　the　results　of　pilot　test　and　full　scale　plant.　The　results　showed　that　primary　fermentation　can　increase　influent　index　such　as　ρ(BOD5),　ρ(CODcr),　ρ(TP),　ρ(SP),　ρ(SS)　comparing　the　effluent　from　full　scale　plant　primary　sedimentation,　separately　increased,　61.1%,　36.5%,　36.1%,　17.36%　and　52.0%,　also　the　biologic　catabolism　index　improve　20.40%,　and　the　technology　especially　in　favor　of　the　influent　VFA,　increased　from　12　to　56,　about3.7　times,　enhance　biological　phosphorus　and　nitrogen　removal　to　the　biological　system.　The　technology　of　sludge　fermentation　can　be　applied　to　the　municipal　wastewater　treatment　plant　where　the　quantity　of　the　carbon　source　is　low　and　difficult　to　biological　phosphorus　and　nitrogen　removal　in　high　efficiency.