The invention discloses a technical method for preparing ammonium nitrate melt, belonging to the technical field of ammonium nitrate preparation. The technical method of the invention includes the steps of amino acid pressurized neutralization, evaporation and concentration, processing and recycling of neutralized wastewater, etc. The step of pressurized neutralization adopts the mode of internalcirculation to pressurize an ammonium nitrate neutralizer, and implements a plurality of control measures and a safety interlocking system (gas ammonia filtration, temperature control, pressure control and PH value control) to ensure the safe and stable running of the reaction during the pressurized neutralization; neutralized steam has high value of heat enthalpy, can meet the requirements of each process during the preparation of nitramine and can greatly save the outside steam, e.g. the process of the invention can save the steam nearly by 200 kg when 1000 kg of ammonium nitrate melt is prepared; and the technical method adopts the unique ammonia recycling process and an ion exchange system to treat waste steam, can realize the purpose of utilizing the waste, and does not pollute the environment.