The invention discloses a safe utilization system of coking fly dust. The system comprises a collection system, a powdering system, a grinder, a main pipe, a powdering pipeline assembly and a maintenance pipeline assembly, wherein the grinder is internally provided with the powdering system, the powdering system is internally provided with a temperature measuring instrument and a first oxygen content detector; the top of the powdering system is provided with a dust outlet communicated with the collection system, the lower portion of the powdering system is communicated with an inlet of the main pipe, and an outlet of the main pipe is respectively communicated with the powdering pipeline assembly and the maintenance pipeline assembly; and the main pipe is provided with a second oxygen content detector and a main switch valve. The safe utilization system of the coking fly dust has the advantages that the whole structure is simple, the cost is low, the operation is stable and reliable, and the professional technical problem that the safe utilization of the fly dust is difficult is effectively solved.