The anaerobic granular sludge was inoculated in an anaerobic reactor, and the simulated wastewater containing glucose and nitrite was used to analyse the process of methanogenesis and dennitrication. The results showed that while the loading rate of COD was increased from 1.5 to 10.5 kg·m-3·d-1 and that of NO2- -N from 0.15 to 1.05 kg·m-3·d-1 during the 50 d operation ofof the reactor, the removal efficiencies of COD and NO2- -N reached more than 80% and 98%, respectively. The reactor was used to treat the animal manure. The removal efficiency of COD was increased from 50% to 80% and that of NO2- -N reached more than 98%, while the loading rate of COD increased from 2 to 7 kg·m-3·d-1, and NO2- -N from 0.2 to 0.7 kg·m-3·d-1. Therefore, the results indicated that it was possible to remove bots nitrogen and organic matter of the animal manure through denitrification and methanogenesis process in the same reactor.