The performance of denitrification in the zeolite biological aerated filter and the biological removal were studied experimentally. The results show that the removal rate of COD is 67% to 90%, that of NH3—N from 52% to 82%, and that of TN from 33% to 67% under the conditions of organic loading 0.8～6.4 kg COD/(m3·d), hydraulic loading 1～2 m/h, and air to water ratio 1∶1～4∶1.The rate of nitrification is 0.23 mg/min under the ammonia concentration of 10～30 mg/L. Bacteria can use the ammonia in zeolite. Grading and partitioning water intake can raise the velocity of bioregeneration and reduce the regeneration time.