The utility model relates to a delayed coking device field, specific delayed coking device with multistage function of preheating that says so. The lower cone of two coke drums is wrapped respectivelyand is equipped with electric heater, the lower cone of two coke drums through second tee bend pipe fitting cross the back with get rid of oily house steward and link to each other, it links to eachother with putting void tower and get rid of the oil tank respectively through third tee bend pipe fitting to get rid of oily house steward, be equipped with respectively on the pipeline under secondtee bend pipe fitting and two coke drums between the cone and get rid of oil and cut off sub - valve, be equipped with on getting rid of oily house steward and get rid of oil wall main valve, the preheat governing valve that be used for adjust coke drum preheating speed is equipped with respectively at third tee bend pipe fitting and on putting void tower and getting rid of the pipeline between the oil tank. The utility model discloses an all wrap to be equipped with in the cone under two coke drums and preheat the electric heater unit who goes on supplying to high -temperature oil -gas well to reducing temperature difference change and leading to the fact the harm to the coke drum, required absorptive heat when satisfying the raw oil thermal cracking improves product quality.