The invention provides a manufacturing method of modified ammonium nitrate, which is suitable for engineering application and comprises the following steps: (1) using one or more than two mixed solvents of liquid carbon dioxide, or liquid halogenated hydrocarbons or liquid ammonia to dissolve ammonium nitrate and a modifier; (2) separating the solvents from solute to obtain the modified ammonium nitrate and gasified solvents. Compared with the prior art, the method of the invention has the beneficial effects that the solvents used for dissolving the ammonium nitrate and the modifier exist under the condition of low temperature or pressurization, are easy to gasify under ambient temperature or no pressurization, and can be easily separated from the ammonium nitrate and the modifier without solvent residue; the operating temperature is low with no need of high temperature heating and high safety; the production efficiency is high, the product itself does not contain water, and long time drying processing is not needed; the solvent can be recycled, and the whole process has no discharge of three wastes, thus the method is green; and the technological process is simple, and the technological equipment investment is not high, thus being easy to realize engineering application.