The antihygroscopicity and anticaking capacity of ammonium nitrate (AN) coated with cerium (Ⅲ) n-dodecylbenzene sulfonate (CDBS),cerium (Ⅲ) stearate (CSA) and octadecylamine nitrate (ON) were studied. The results show that compared with pure AN,the hygroscopicity and caking capacity of AN coated CDBS,CSA and ON decrease obviously. And the reasons of reducing the hygroscopicity and caking capacity of AN were theoretically analyzed. The composite additive composed of CDBS,CSA and ON has more anticaking capacity and antihygroscopicity than their single additive and the efficiency of the liquid coating is better than that of the mechanical mixing. The coating temperature and adding order of composite additive are two principal factors affecting the anticaking capacity.