A laboratory-scale biotrickling filter was evaluated for its effectiveness in treating waste gases containing ammonia at different inlet loading rates. The inlet concentration of ammonia varied from 20～300mg/m3, and the air flow rates were 0.61m3/h, 0.85m3/h and 1.06m3/h, equivalent to empty bed residence time of 35s, 25s and 20s, respectively. The experimental results showed that the inlet ammonia can be efficiently removed in the biotrickling filter. The removal efficiency was nearly 100% when inlet ammonia loading rate was below 28.33g/m3·h, and the maximum elimination capacity for the biotrickling filter was determined to be about 33.99 g/m3·h. The results in microbial analyses had proven that the ammonia oxidizing bacteria and nitrite oxidizing bacteria were dominant in the biotrickling filter. These results show that the treatment system studied can be considered as a viable alternative for the treatment of gaseous emissions containing different concentrations of ammonia.