The start-up and operation performances of EGSB were investigated for municipal sewage treatment, and the key operational parameters were also analyzed. After 45 days, EGSB could be started-up effectively with the removal of CODCr and NH3 -N being 58.8% and 32.9%, respectively. In the mean time, the removal efficiency of ammonia and nitrite were from negative to positive, and the anammox strengthened gradually. It was also found that the reactor operated well at ambient temperature with the average CODCr removal efficiencies of 66.6%. The average removal efficiencies of NH3 -N, NO2- -N and NO3- -N were up to 90% and the anammox appeared markedly in this system. The quality of the effluent in the system could meet grade I of Integrated Wastewater Discharge Standard (GB 8978—1996). It was suggested that the HRT of EGSB in operation is less than 2 h and the reflux ratio less than 400%.