Effect of different organic substrate concentration on nitrogen removal in SNAD and the application of this process to treat domestic wastewater were investigated in a MBR, with gradually increased glucose as a source of organic matter. Besides, changes of microbial communities were observed by PCR-DGGE techniques. Experimental results and DGGE profiles showed that the increase of organic carbon concentration did not inhibited the activity and category species of AOB and Anammox bacteria when the C/N ration was ranged 0 to 2.0. Meanwhile, a significantly improvement of nitrogen removal was observed via effective denitrification, with a total nitrogen removal efficiency of 67% and nitrogen removal rate of 0.34 kg/(m³·d), respectively. Under the C/N of 3-4 condition, the anammox bacteria in the system changed insignificantly, but AOB was inhibited and the category species reduced, resulting a decreasing of nitrogen removal efficiency.Total nitrogen removal efficiency and nitrogen removal rate were about 73% and 0.17 kg/(m³·d), respectively.Nitrosomonas and Candidatus Kuenenia stuttgartiensis were the predominant microorganisms in the SNAD reactor and played a major role in autotrophic nitrogen removal.