In this study the effect of simultaneous employment of ultrasonic wave radiation, chemical substance of ionic liquid and operating conditions of thermal cracking is investigated experimentally on upgrading the atmospheric residue (AR) of a crude oil atmospheric distillation tower. Five main factors of this process that are investigated are ionic liquid concentration, ultrasonic wave power, ultrasonic radiation time, temperature and pressure. According to Box-Behnken Design, 46 experiments are conducted. Then, the proper experimental condition of this process is determined and hence, based on Multilevel Categoric Design the efficiency of seven different kinds of ionic liquids is compared. According to this design, 14 experiments are conducted. The results of 46 experiments conclude that this process is able to upgrade AR and even the simultaneous employment of ionic liquid, ultrasonic and thermal cracking cause a synergistic effect on AR upgrading. Also, the results of 14 experiments indicate that 1-Propyl boronic acid-3-decylimidazolium bromide is a desirable ionic liquid for this process.