Blast furnace slag, which is the main by-product of the ironmaking process discharged at 1450 °C, contains high-quality sensible heat, while oily sludge is the main solid waste produced in the process of gas exploration, storage, and transportation. The energy and resource utilization of blast furnace slag is complementary to the environmentally friendly treatment of oily sludge, which has provided a new idea for the multi-factor synergistic cycle and energy transformation of the two wastes. The pyrolysis of the oily sludge with the molten blast furnace slag was conducted in the current paper. Results showed that the oily sludge was rapidly pyrolyzed, and the heavy metal elements in the oily sludge were solidified. The solidification rate of the heavy metals exceeds 90%, except for vanadium. The reconstituted water-quenched blast furnace slag still has good activity, and it will not affect the further use of the slag after pyrolysis (BFS-P).