The　physicochemical　properties　of　powdered　activated　carbon　(PAC)　are　important　factors　affecting　its　adsorption　performance,　which　is　also　related　to　the　characteristics　of　target　organic　pollutants.　In　this　study,　the　key　indicators　affecting　the　adsorption　performance　of　PAC　were　identified,　and　the　physicochemical　properties　of　PACs　were　modified　by　hydrogen　peroxide　and/or　ultrasound　in　a　targeted　manner　to　improve　the　adsorption　performance.　The　results　indicated　the　adsorption　properties　of　printing　and　dyeing　secondary　effluent　organic　matter　(EfOM)　in　terms　of　CODcr　and　UV　absorbance　at　254　nm　(UV254)　positively　correlated　with　mesoporous　volume,　average　pore　size　and　acid　group　content　of　PAC.　After　modification,　the　mesoporous　volume　and　average　pore　size　of　PAC　increased,　and　the　number　of　acidic　groups　increased,　thus　enhancing　the　adsorption　efficiency.　EfOM　removal　characteristics　showed　that　PAC　preferentially　adsorbed　unsaturated　bonds　or　aromatic　compounds,　tryptophan-like　proteins,　soluble　microbial　metabolites　and　low　molecular　weight　fractions　below　1　kDa.　In　addition,　the　relative　contents　of　specific　surface　area,　pore　volume　and　oxygen-containing　functional　groups　(O-C--O,　C-OH,　C--O/O-C-O)　of　PAC　decreased　after　adsorption,　indicating　that　EfOM　adsorption　was　a　physical　and　chemical　process,　including　pore　filling,　hydrophobic　interaction　and　chemical　bond　force　interaction.　In　general,　PACs　with　larger　mesoporous　volume,　average　pore　size　and　abundant　acid　groups　possessed　good　adsorption　performance　towards　EfOM.