The invention provides a method for preparing high-nitrogen steel through a combination of pressurized induction and protective-atmosphere electro-slag remelting. High-nitrogen martensitic steel or high-nitrogen austenitic steel serves as the high-nitrogen steel. The method comprises the following steps such as raw material preparation, determination of the melting pressure and the pouring pressure, pressurized induction melting, deoxidization, pouring, and electro-slag remelting. The method provided by the invention has the advantages that the solidification velocity of the electro-slag remelting process is relatively high, so that the escape of nitrogen can be inhibited, a high-nitrogen steel remelting ingot of which the nitrogen content is slightly higher than the normal-pressure solubility is obtained, and the prepared high-nitrogen steel is excellent in corrosion-resistant property and mechanical property; and in order to reduce the production cost of the high-nitrogen steel, a new way for preparing the high-nitrogen steel of which the nitrogen content is slightly higher than the normal-pressure solubility by adopting the protective-atmosphere electro-slag remelting process is provided.