The present invention falls within the field of purifying oil-laden wastewater, which provides a method for purifying coke-cooling wastewater in a delayed coking process in petroleum chemical field. The method comprises the following steps: (a) cooling the coke-cooling wastewater produced in a delayed coking process to 5-55.degree. C. under 0.1-0.25 MPa absolute pressure, to obtain cooled coke-cooling wastewater; (b) subjecting the cooled coke-cooling wastewater to solid-liquid separation, to obtain a coke breeze phase and a liquid phase; (c) further separating the obtained liquid phase, to obtain an oil phase and a water phase; and (d) further discharging water from the obtained oil phase, to obtain the separated oil phase. The present invention also provides an equipment for carrying out the method. The method of the present invention has the following advantages: low cost for the equipment, good effect for treating coke-cooling wastewater, effectively preventing sulfur pollution and foul odor pollution, saving resources and improving the overall utility of the resources, and improving the cool coking efficiency.