2-acetyl thiophene was synthesized under ultrasonic irritation. Effects of reaction time, reaction temperature and the adding order of reactant and catalyst on yield were experimentally studied. The results show that under ultrasound irradiation, the reaction condition of synthesis of 2-acetyl thiophene becomes mild, reaction time is shortened and reaction temperature is lowered, higher yield is obtained. It can be seen that ultrasonic irritation is a potential cleaner technology.