Phosphomolybdic　acid,　a　green　and　strong　oxidant,　can　not　only　promote　the　hydrolysis　in　the　process　of　anaerobic　fermentation　of　waste　activated　sludge　(WAS),　but　also　inhibit　the　methanogenic　microorganisms　effectively,　but　the　specific　role　of　phosphomolybdic　acid　along　with　pH　adjustment　on　the　production　of　volatile　fatty　acids　(VFAs)　is　still　unknown.　This　study　proposed　a　method　to　optimize　the　anaerobic　fermentation　of　WAS　by　controlling　the　initial　pH　(7,　8,　9,　10)　and　phosphomolybdic　acid.　Results　showed　that　increasing　the　initial　pH　and　dosing　phosphomolybdic　acid　were　beneficial　to　the　release　of　organic　matter　from　WAS,　which　promoted　the　production　of　volatile　fatty　acids　(VFAs).　Especially　when　the　initial　pH　was　10,　the　maximum　VFAs　production　(1588.7mg　COD/L)　was　2.0　times　that　of　the　unregulated　initial　pH　(778.1mg　COD/L),　and　the　proportion　of　acetic　acid　reached　48.7%.　Therefore,　phosphomolybdic　acid　and　alkaline　condition　played　a　synergistic　effect　on　the　anaerobic　fermentation　process,　for　which　the　production　of　VFAs　could　be　increased.　©　2023　Chinese　Society　for　Environmental　Sciences.　All　rights　reserved.