The invention provides a method and a device for cracking and recovering waste petrochemicals. The device comprises a cracking reaction furnace, a filter, a first cooler, a 100-mesh filter, a second cooler, an oil gas collector, a first oil water separator, a basic cracking oil groove, a first vacuum pump, a fractionation furnace, a third cooler, a second oil water separator, a finished product oil groove, a second vacuum pump, a gas wash tower, a gas pneumatic trough and a plurality of product oil grooves, wherein the waste petrochemicals are put in a reaction furnace of the cracking reaction furnace and mixed with waste liquefied petrochemicals and initial agents according to preset ratios, the mixture is heated up to the preset temperature, and the waste petrochemicals are primarily decomposed to oil gas, and the oil gas undergoes repeated treatments of filtering, cooling, oil-water separation and fractionation, and the waste petrochemicals are cracked and rectified into different oil products.