The invention discloses a multi-segment combined nitrogen control method of high-strength microalloyed steel. The multi-segment combined nitrogen control method comprises the following steps: a converter vanadium extracting process, a converter melting process, an LF (Ladle Furnace) refining process and a slab continuous casting protective casting process; the content of finished steel of the microalloyed steel is less than or equal to 0.005 percent. According to the multi-segment combined nitrogen control method disclosed by the invention, a slag layer with a certain thickness is formed on the surface of molten steel, so that a function of isolating air is obtained; a mode of firstly adding alloy materials with weak deoxidizing capacity and then adding alloy materials with strong deoxidizing capacity is adopted, so that the phenomenon of nitrogen increment caused by contact between the molten steel with the air due to a strong deoxidizing reaction in a steel ladle is prevented from happening; after tapping is ended, a steel ladle car can be driven to an argon blowing operation station, argon blowing and stirring can be carried out for 2 minutes, and the content of O in the molten steel is regulated to be less than or equal to 0.002 percent; the electric heating time is controlled through LF refining, calcium carbide is added in batches during a refining and heating process, so that furnace slag can be formed into good foam slag, the foam slag covers the surface of the molten steel to form a protective layer, and direct contact between the air and the molten steel is isolated. Through combined control of the processes, the microalloyed steel is finally obtained, and the content of N in the finished steel of the microalloyed steel is less than or equal to 0.005 percent.