In　this　study,　an　experimental　study　aimed　at　optimizing　the　factors　affecting　the　regeneration　amount　of　4-chlorophenol　(4-CP)　from　spent　powdered　activated　carbon　(PAC)　is　presented.　For　this　response　surface　methodology　(RSM)　with　Box-Behnken　design　was　applied,　which　identified　four　variables　(acoustic　density,　NaOH　concentration,　spent　PAC　dosage　and　ethanol　concentration)　in　batch　experiments.　The　physicochemical　characteristics　of　the　regenerated　PAC　under　the　optimal　desorption　condition　was　evaluated　using　thermogravimetric　analysis,　Fourier　transform　infrared　spectroscopy　(FTIR),　Brunauer-Emmett-Teller　(BET)　and　scanning　electron　microscopy,　as　compared　with　the　virgin　and　spent　PACs.　Among　the　four　variables,　acoustic　density　and　ethanol　concentration　(v/v,　%)　had　stronger　effect　on　the　4-CP　desorption　(p　＜　0.001).　The　predicted　optimal　4-CP　desorbing　amount　was　97.43　mg　g(-1),　and　this　matched　well　the　observed　performance　of　(96.94　+/-　0.70)　mg　g(-1),　obtained　by　acoustic　density　of　0.36　W　mL(-1),　NaOH　concentration　of　0.10　mol　L-1,　spent　PAC　dosage　of　0.93　g　L-1　and　ethanol　concentration　(v/v)　of　24%.　The　result　of　thermogravimetric　pyrolysis　profiles　of　regenerated　PAC　confirmed　that　the　adsorption　behavior　of　4-CP　exhibited　a　chemisorption　feature　and　desorption　process　was　dominated　by　chemical　reaction.　Analysis　of　FTIR,　pore　structure　and　BET　surface　area　demonstrated　that　ultrasound　mainly　acted　on　the　surface　functionalities,　macro-pore　and　meso-pore　structure　of　PAC.　Additionally,　the　SEM　images　indicated　that　cavitation　effect　affected　the　surface　roughness　and　surface　cavities　of　PAC.　The　results　here　provided　an　insight　into　the　application　of　ultrasound　to　regenerate　saturated　PAC　with　4-CP.