This paper presents a developed ecological function for absorption refrigerators with fourtemperature-level. Moreover, aforementioned absorption refrigerator is optimized by implementing ecological function. With the aim of the first and second laws of thermodynamics, an equivalent system is initially determined. To reach the addressed goal of this research, two objective functions: the coefficient of performance (COP) and the ecological function (E) have been involved in optimization process simultaneously. The first aforementioned objective function has to maximize the rest objective functions, on the other hand, have to maximize in parallel optimization process. Developed multi objective evolutionary approaches (MOEAs) on the basis of NSGA-II method are implemented throughout this work.