To　resolve　membrane　fouling　in　the　ultrafiltration　process　of　sewage　effluent,　the　impact　of　activated　carbon　catalytic　ozonation　(AC/O-3)　on　fouling　control　was　investigated.　The　influence　of　initial　pH　on　AC/O-3　for　fouling　alleviation　was　further　explored.　The　results　revealed　that　AC/O-3　pretreatment　greatly　mitigated　the　membrane　fouling.　The　total　fouling,　reversible　fouling,　and　irreversible　fouling　were　all　decreased.　The　initial　pH　influenced　the　alleviation　effect　of　AC/O-3　on　fouling　control　obviously,　although　it　only　slightly　impacted　the　AC　adsorption　pretreatment　on　fouling　alleviation.　Besides,　there　was　no　obvious　impact　of　pH　on　the　ultrafiltration　process.　Compared　with　the　adjustment　of　initial　pH　during　ultrafiltration　and　the　pretreatment　methods　such　as　AC　adsorption　and　preozonation,　AC/O-3　displayed　the　greatest　effect　on　both　fouling　alleviation　and　permeate　quality　improvement　under　all　pH　conditions.　It　was　the　component　transformation　of　sewage　effluent　after　AC/O-3　pretreatment　that　caused　the　alleviation　of　membrane　fouling.　With　the　increase　in　initial　pH,　the　high-MW　biopolymers　as　well　as　humic　substances　in　the　effluent　organic　matter　could　be　preferentially　removed　by　AC/O-3,　which　mitigated　the　flux　decline　during　the　ultrafiltration　process　and　decreased　the　reversible　and　irreversible　fouling.