The　characteristic　of　phosphorus　removal　and　appropriate　change　of　the　traditional　operation　modes　were　investigated　in　UniFed　sequencing　batch　reactor　(SBR)　laboratory-scale　apparatus　(40　L),　treating　actual　domestic　wastewater　with　low　ratios　of　C/N　(2.57)　and　C/P　(30.18),　providing　theoretical　basis　for　actual　application　of　wastewater　treatment　plant.　UniFed　SBR　system　with　its　unique　operation　mode　had　the　distinct　superiority　of　phosphorus　removal.　On　this　occasion,　the　effect　of　volumetric　exchange　ratio　(VER)　and　the　method　of　influent　introduction　for　phosphorus　removal　were　studied.　When　the　carbon　source　became　the　limiting　factor　to　phosphorus　release,　the　higher　the　VER,　the　lower　the　phosphorus　concentration　in　the　effluent.　Three　different　influent　patterns,　including　one-time　filling,　four-time　filling,　and　continuous　filling　with　the　same　quantity　of　wastewater　could　increase　the　release　rate　of　anaerobic　phosphorus　from　0.082　to　0.143　mg　center　dot　P　center　dot(L　center　dot　min)(-1).　Appropriate　change　of　the　traditional　operation　modes　could　optimize　the　efficiency　of　phosphorus　removal.　When　the　feed/　decant　time　was　extended　from　2　h　to　4　h,　the　phosphorous　removal　efficiency　increased　from　59.93%　to　88.45%　without　any　external　carbon　source.　In　the　mode　of　alternation　of　anoxic-aerobic　(A/O)　condition,　phosphorous　removal　efficiency　increased　from　55.07%　to　72.27%　clearly.　The　carbon　source　in　the　influent　can　be　used　adequately,　and　denitrifying　phosphorus　removal　was　carried　out　in　anoxic　stage　2　(A2).　This　mode　was　optimal　for　the　treatment　of　actual　domestic　wastewater　with　low　C/N　and　C/P　ratios.