The granular fertilizer formed by the fertilizer granulator has high moisture content and shall be dried to meet the standard. Rotary drum drying machine fertilizer dryeris mainly used for drying fertilizer with certain humidity and particle size in the compound fertilizer and organic fertilizer production. The dryer drum is also suitable for drying other materials. After drying, the moisture content of compound fertilizer will be reduced to 2%-5% from 20%-30%, while the moisture content reducing range for organic fertilizer is from 40%-10%. Rotary dryer shall be used combining with cooling machine, as fertilizer granules after drying has high temperature, which is not good for storage.