The present invention relates to a method for preparing amicarbazone by using amino triazolinone which is an intermediate compound and relates to a method for preparing amicarbazone comprising the steps of: obtaining hydrazine carboxylic acid represented by chemical formula (V) by reacting acylhydrazide represented by chemical formula (II) and a carbamating agent represented by chemical formula (III) or (IV) reacting the obtained hydrazine carboxylic acid represented by chemical formula (V) and hydrazine hydrate in the presence of a base catalyst and reacting the obtained compound represented by chemical formula (I) and an alkyl isocyanate represented by chemical formula (IV) in the presence of a base catalyst. Amino triazolinone and amicarbazone would be stably produced by the present invention without safety gear and safety facilities for the leakage of phosgene which has been conventionally used as a reactant. Therefore it would be possible to reduce the preparation cost of amicarbazone which is used as a herbicide for field crops such as sugarcane corn and the like thereby increasing price competitiveness. Additionally it would be possible to increase the cost competitiveness compared with other herbicides.
