The present invention provides a catalytic cracking fractionation and absorption-stabilization system, and energy saving method thereof; the present invention is to arrange a waste heat refrigerator of the main fractionating tower, a waste heat refrigerator of rich gas and a waste heat refrigerator of stabilizer in a catalytic cracking fractionation and absorption-stabilization system so as to utilize low temperature waste heat at the top of a main fractionating tower, rich gas, stable gasoline, intermediate heat exchange flow of an absorber of the system as a refrigerator driving heat source; in order to cool naphtha and circulating gasoline to a low temperature lower than 40° C., control low temperature operations of the absorber and reduce the heat load of a desorber and a stabilizer, and the heat extracted by the refrigerators is cooled by cooling water with a higher temperature so as to reduce the consumption of the cooling water. In addition, developed residual pressure generating units and waste heat generating units coordinate to convert medium and low pressure of the dry gas and low-grade waste heat of other products in the system into electric energy that can be conveyed into a grid, therefore the electricity consumption of a dry gas compressor can be supplemented, and the operation cost of the system is reduced to the minimum.