The　effect　of　pH　value　(4.0-12.0)　of　soluble　chemical　oxygen　demand　(SCOD),　volatile　fatty　acid　(VFAs),　nitrogen　and　phosphate　production　in　the　activated　sludge　hydrolysis　process　was　investigated　at　ambient　temperature　by　batch　experiments.　The　experiment　results　showed　that　the　sequence　for　hydrolysis-acidification　efficiency　of　activated　sludge　was:　alkaline　station,　acidic　station　and　neutral　station.　When　the　pH　value　was　between　6.0　and　11.0,　the　efficiency　increased　with　the　increasing　of　pH,　but　when　the　pH　was　at　12.0,　the　activated　sludge　hydrolysis-acidification　efficiency　decreased　because　of　the　browning　reaction.　It　was　observed　that　the　SCOD　and　VFAs　production　increased　as　the　reaction　time　prolonged.　While　pH　changed　between　the　ranges　of　4.0-11.0,　ρSCOD　and　ρVFAs　reflect　a　trend　of　declining　first　and　then　rising,　with　the　neutral　pH　as　the　division　point.　When　pH=11.0　the　concentrations　of　SCOD　and　VFAs　were　the　highest,　and　the　data　were　2599　and　749mg/L,　respectively.　However,　the　concentrations　of　NH4+-N　and　PO43--P　reached　the　maximum　when　pH=4.0　with　the　data　of　208.1　and　193.4　mg/L,　respectively.　Thus,　by　using　pH　value　as　the　controlling　parameter　higher　efficiencies　of　sludge　hydrolysis　and　acidification　could　be　achieved.　Especially　when　pH　value　was　between　10.0　and　11.0,　higher　fermentation　efficiencies　and　lower　rates　of　nitrogen　and　phosphate　releasing　can　be　realized.　This　can　bring　more　carbon　source　for　nitrogen　and　phosphorus　removal　and　reduce　the　quantity　of　excessive　activated　sludge　within　the　wastewater　treatment　system.