Based on the national  policy of  controlling the ammonium nitrate , a plan to modify the ammonium nitrate with monoammonium phosphate was put forward. In order to meet production requirement, the performance indexs of the mixing solution were tested, for example, the melting condition, the heat stability and the viscocity. According the experiment results, the quality indexs of the modified ammoium nitrate with monoammoium phosphate for the production of the compound fertilizer were put forward.