In　order　to　study　the　effect　of　different　fermentation　styles　on　the　waste　activated　sludge　(WAS)　anaerobic　fermentation　performance　and　the　utilization　of　fermentation　liquor　by　microorganism.　The　WAS　were　fermented　in　the　Ca(OH)2(pH=10±0.2),　Ca(OH)2+NaCl(pH=10±0.2),　FNA(pH=5.5±0.2),　PMS,　SDBS　and　naturally　fermentation　system,　and　the　fermentation　liquor　was　used　to　de-nitrification　of　biology.　Different　indicators　were　analyzed　respectively　such　as　dissolution　of　organic　matters　(SCOD),　short　chain　volatile　fatty　acids　(SCFAs),　soluble　protein,　soluble　polysaccharide,　key　enzyme　(hydrolase　and　coenzyme420)　and　NO3--N.　The　results　showed　that　the　hydrolytic　acidification　performance　and　fermented　liquid　utilization　of　six　fermentation　systems　had　significant　difference.　The　maximal　values　of　SCOD,　SCFAs,　hydrolase　activity　and　sludge　reduction　appeared　at　Ca(OH)2+NaCl　fermentation　system,　and　Ca(OH)2　fermentation　system　was　followed,　but　the　naturally　fermentation　system　was　minimum.　Although　the　protein　and　polysaccharide　was　abundant　in　the　FNA　fermentation　system　as　same　as　Ca(OH)2+NaCl　fermentation　system,　but　lower　hydrolase　and　higher　F420　activity　led　to　the　lower　SCFAs　accumulation.　The　de-nitrification　tests　showed　that　the　fermented　liquid　from　Ca(OH)2　and　Ca(OH)2+NaCl　fermentation　systems　had　a　remarkable　de-nitrification　effect　and　large　of　NO2--N　accumulation　which　was　similar　to　sodium　acetate,　but　the　fermented　liquid　from　FNA,　PMS　and　SDBS　fermentation　systems　could　not　be　well　used　by　microorganism　because　of　large　of　poisonous　substance.　©　2016,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.