The invention discloses a delayed-coking exhaust gas treatment method. According to the method, sulfur-bearing sewage enters a steaming-out vent tower for cooling and oil-water separation, part of heavy sump oil of a tower bottom of the steaming-out vent tower flows back to the bottom of steaming-out vent tower, the other part of the heavy sump oil enters the middle part of the steaming-out vent tower, light sump oil and sewage of a tower top of the steaming-out vent tower enter an oil-water separating tank for oil-water separation at the temperature of 30 DEG C to 60 DEG C, the light sump oil is discharged from the top of the oil-water separating tank, the sewage enters a sewage tank for treatment, by the treatment of the sewage tank, coke powder is discharged from the bottom of the sewage tank, the light sump oil is discharged from the upper part of the sewage tank, and purified sewage is discharged from the lower part of the sewage tank. According to the method, the problem that sulfur-bearing sewage of the top of the vent tower is emulsified and is high in oil and coke powder content is solved.