The invention discloses a steel additive agent vanadium nitride alloy powder core-spun wire and relates to a vanadium nitride alloy additive agent product used for increasing vanadium and nitrogen of molten steel in a steel smelting process. The core-spun wire comprises a core layer and an outer steel layer, wherein the core layer is made into a wire shape through the outer layer by using a core-spun machine. The core layer contains 75-97 percent of vanadium nitride alloy powder, 3-20 percent of metallic aluminum powder and 0-10 percent of carbon powder, wherein the vanadium nitride alloy powder is a mixed powder raw material obtained by compounding with vanadium compound powder and carbon powder, and at an appropriate temperature, the mixed powder raw material is reduced and nitrided by ammonia or ammonia-nitrogen mixed gas to directly obtain the vanadium nitride alloy powder. During smelting, the core-spun wire is directly and deeply inserted into the molten steel by utilizing equipment such as a wire feeder, and the like, which can ensure that vanadium nitride alloy can be better dissolved into the molten steel so as to improve the recovery rates of the vanadium and the nitrogen during smelting steel. Meanwhile, the contents of the vanadium and the nitrogen in the molten steel can be stably controlled so as to improve the stability of steel in large-scale industrial production.