The invention relates to a reinforcing agent for brazing filler metal for high-nitrogen steel brazing. The reinforcing agent is nickel-plated graphene or vanadium-plated graphene or a mixture of the nickel-plated graphene and the vanadium-plated graphene in any proportion, and when the reinforcing agent is added to the brazing filler metal, the adding amount is 2.5-4% of the total weight of the brazing filler metal. The main body of the reinforcing agent is composite graphene particles, and when the reinforcing agent is added to the brazing filler metal, the microstructure and performance of the brazing filler metal can be optimized; the joint strength of the brazing filler metal for connecting high-nitrogen steel is enhanced, and the service life of high-nitrogen steel devices is prolonged; when the reinforcing agent is added to the brazing filler metal and then the high-nitrogen steel is brazed, the base metal of the high-nitrogen steel hardly melts, so that nitrogen elements do notlose, the defect of air holes in a traditional welding mode is overcome, nitrogen elements are hardly lost, the connection strength and mechanical properties of a joint are improved to a certain extent, and the welding joint is formed very well.