Abstract: The industrial process for acetophenone production is by the reaction of benzene with acetyl chloride, which produces strong acid, and is an environmental pollution process. A alternative approach for the synthesis of acetophenone by liquid-phase oxidation of ethylbenzene is studied using manganese sulfate as catalyst and oxygen as oxidant. With optimized reaction conditions [5mL of ethylbenzene, 4.9% of MnSO4, n（Br）/n（Mn）=2.0, 10 mL of glacial acetic acid, 100mL/min of oxygen flow at 90℃ with 4 h of reaction time], conversion of ethylbenzene and yield of acetophenone reached to 72.36% and 59.57%, respectively.