Abstract: Using batch tests,the nitrifying performances were investigated at different temperatures(10,15,20,25,30 ℃) and free ammonia(FA) concentration ρ(FA)(1.76,8.23,14.68,26.52,46.23,90.00 mg/L) between the Aerobic granular sludge(AGS) and the Floccular sludge(FS).Results show that the specific ammonia oxidation rates of AGS and FS significantly increase with the temperature,however,at the same temperature,the ammonia oxidation rate of AGS is 4.5 times(10 ℃) and 2.5 times(30 ℃) of that of FS.When ρ(FA)=90.00 mg/L,experiments show that FA has no significant inhibitory effect on AGS but FS,the ammonia oxidation rate of FS decreases by 43% compared with last FA level.This is because the stronger resistance of AGS to the transfer of ammonia into the bacterial aggregates may make it appear to be more tolerant to FA.But in the FS,distributing throughout the entire aggregates,the ammonia oxidizing bacteria(AOB) are more possibly inhibited under high FA loading rate.It can be concluded that the AGS has great potential in withstanding high ammonia loading and maintaining the stability of the biological nitrogen removal performance.