Objective To establish an ion chromatography (IC) method for detection of ammonia in the environmental air of laboratory animal facilities. Methods Dilute sulfuric acid was used as the absorption liquid to collect ammonia in the air. Ammonia was converted into ammonium ion in the absorption solution. With methylene sulfonic acid as the pouring liquid, the content of ammonium ion in the absorption solution was detected, and the concentration of ammonia in the air was calculated. Results The ammonium ion showed good linearity in the range of 0 to 1 μg/mL (r=0.9994), and high precision (RSD<6.38%). The lowest detected concentration was 0.012 mg/m³, and the average recovery was 98.8%. Conclusions This is a simple method, easy to operate, not interfered by other ions, and can be used to detect the ammonia in the environmental air of laboratory animal facilities.