In　order　to　obtain　a　more　efficient　method　of　manganese(II)　removal,　jar　test　was　used　to　study　the　effect　of　potassium　manganese(K2MnO　4)　pre-oxidation　on　aluminum　chloride　(AlCl3)　coagulation　to　remove　manganese(II).　It　was　investigated　that　the　effect　of　the　dosage　of　K2MnO4,　dosing　time,　sedimentation　time　and　common　ions　on　manganese(II)　removal.　The　results　showed　that,　when　K2MnO　4　was　added　before　AlCl3　and　its　dosage　ranged　from　2.87　mg/L　to　4.31　mg/L,　with　the　sedimentation　time　longer　than　5　minutes　(min),　the　manganese(II)　removal　rate　can　achieve　82%　even　100%.　Acid　and　neutral　condition　was　adverse　for　manganese(II)　removal,　while　alkaline　condition　can　achieve　better　results.　The　optimal　pH　was　9.20.　The　effect　on　manganese(II)　removal　of　calcium　ion(Ca2+)　and　magnesium　ion(Mg2+)was　unconspicuous,　whereas　phosphate　ions(PO43-)　had　some　negative　effect.　The　effect　of　AlCl3　to　remove　manganese(II)　in　the　way　of　coagulation　can　be　enhanced　by　using　K2MnO4　oxidation　and　coagulation　aid,　which　was　a　kind　of　fairly　effective　technology　for　manganese(II)　removal.　©2009　IEEE.