An　improved　mathematic　model　of　management　of　filters　in　a　fluid　power　system　(FPS)　under　uncertainty　was　developed　in　this　article　based　on　the　former　hybrid　optimization　method.　The　model　integrated　the　interval-fuzzy　quadratic　programming　model　into　an　improved　model　of　contaminant　control　for　the　selection　of　filters　finenesses,　the　estimation　of　service　life　of　pumps,　and　replacement　strategies　of　filters　in　an　FPS　under　uncertainty.　The　fuzzy　quadratic　optimization　approach　was　used　in　the　model　to　handle　the　uncertainties　existing　not　only　in　the　contaminant　holding　capacity,　but　also　in　the　contamination　level　and　contaminant　sensitivity.　The　integrated　model　has　been　applied　in　a　case　of　selecting　filter　fineness　and　planning　allocation　and　replacement　strategies　under　uncertainty　for　an　FPS　with　bypass　filtration　circuit.　All　of　the　scenarios　with　available　filter　fineness　have　been　examined.　The　generated　decision　alternatives　can　help　decision　makers　to　identify　desired　policies　for　contamination　control　under　various　total　costs,　satisfaction　degrees,　and　system-failure　risks　under　different　contaminant　ingression/generation　rates.