In　this　paper,　the　impacts　of　cleaning　conditions　on　the　cleaning　efficiency　of　0.1　mu　m　polyethersulfone　(PES)　membrane　fouled　by　active　sludge　suspension　from　SBR　were　investigated　systematically.　The　experiments　were　performed　in　dead-end　microfiltration　cell,　using　oxalic　acid,　chlorhydric　acid,　citric　acid,　sodium　hypochlorite　and　sodium　hydroxide　as　the　chemical　cleaning　agents.　The　orthogonal　method　was　applied　to　analyze　the　experimental　data.　The　results　showed　that　chemical　cleaning　could　restore　almost　all　of　the　permeate　flux.　However,　its　cleaning　ability　was　reduced　gradually　with　the　increase　of　cleaning　cycles,　which　results　from　the　increasing　accumulation　of　irreversible　foulants　onto　the　membrane　surface　or　in　the　pores.　The　two-stage　chemical　cleaning　procedure　which　uses　sodium　hypochlorite　and　citric　acid　sequentially　is　a　more　effective　way.　The　sequence　of　cleaning　conditions　on　average　change　rate　of　the　cumulative　permeate　volume　is　PHsodium　(hypochlorite)　(22.4%)　＞　PHcitric　acid　(20.3%)　＞　T-sodium　hypochlorite　(16.4%)　＞　V-citric　acid　(14.4%)　＞　T-citric　acid　(13.2%)　＞　T-sodium　hypochlorite　(11.2%)　＞　t(sodium　hypochlorite)　(1.2%)　＞　t(citric　acid)　(0.9%).　Higher　temperature,　more　dosage　volume,　and　strong　basicity　or　acidity　of　the　cleaning　solution　are　beneficial　to　chemical　cleaning　operation.　(C)　2013　Elsevier　B.V.　All　rights　reserved.