In　this　research,　a　test　rig　testing　the　performance　of　a　hydraulic　oil　purifier　based　on　HIGEE　technology　is　established.　Generally,　filler,　cone　angle,　length　of　vortex　finder　and　flowrate　are　considered　as　four　kinds　of　the　most　important　parameters　affecting　the　purification　efficiency　of　the　purifier.　Thus,　each　of　the　parameters　with　four　different　levels　is　investigated　during　the　study.　In　case　of　the　multi-variables　and　multi-level　of　the　experiment,　orthogonal　experiment　is　carried　out　in　order　to　distinguish　the　sensitivity　of　each　parameter.　By　analyzing　the　interaction　between　different　parameters,　optimal　parameter　combination　can　be　obtained　according　to　different　targets　(i.e.　remove　maximum　of　solid　particles　or　moisture).　The　research　will　provide　a　new　method　to　control　the　contamination　in　the　hydraulic　system.　©　2015　IEEE.