In order to make sure the water quality can reach the first-class A standard stipulated in the Pollutant Discharge Standard of Urban Sewage Treatment Plant, the bioaugmentation technology was adopted to improve the performance activated sludge. Compound microbial agents with high efficiency in degrading protein, fat and aniline (consist of heterotrophic nitrifying-aerobic denitrifying strains and denitrifying phosphorous accumulating bacteria) was used to reduce total nitrogen (TN), ammonia nitrogen (NH₃-N) and COD of swage containing food wastewater. The experimental results showed that the effluent water quality had been significantly improved after adding the compound bacteria in the aeration tank. The TN removal rate of the secondary settling tank reached 93.48%, which was increased by nearly 70% on the original basis; the ammonia nitrogen removal rate was 83.15%, increased 60% more than the original basis; COD removal rate reached 91.40%. After the compounding agent matures and forms a commensal flora with the indigenous microorganisms in the aeration tank, the bacteria were stopped to add for 2 months, and during this period, the sludge was controlled to continuously reduce the sludge concentration in the biochemical pool (from 9000mg/L to 6000mg/L). The final system TN, NH₃-N, COD removal efficiency can be maintained at the above level, greatly reducing the energy consumption of the original system.