A high-magnetism sintered neodymium-iron-boron magnet is characterized by comprising, by weight, 27-31% of rare earth elements, 0.9-1.2% of boron, 0-3.0% of cobalt, 0-2% of adding elements and the balance iron, the rare earth elements comprise two or more of neodymium, praseodymium, dysprosium, terbium and holmium, and the adding elements comprise two or more of aluminum, copper, gallium, niobium, zirconium, titanium and hafnium. A manufacturing method includes the working procedures of batching, smelting, hydrogen breaking, pulverizing, forming and sintering, and argon protection is selected for replacing nitrogen protection in the working procedures from smelting to sintering, so that the content of nitrogen in the sintered neodymium-iron-boron magnet is reduced substantially, the total quantity of the rare earth elements in the magnet is relatively stable, the coercivity of the magnet is improved, and the magnetic performance is kept well. A magnet crystal boundary structure change caused by the nitrogen does not exist in the production process, and the corrosion-resistant capacity of the sintered magnet is improved.