A laboratory-scale membrane-aerated biofilm bioreactor (MABR) equipped with nonwoven fabrics support around the gas-permeable carbon tube was developed for single-stage autotrophic nitrogen removal based on partial nitrification and anaerobic ammonium oxidization. Initially, the reactor was inoculated with nitrifying biomass. By decreasing the air pressure in the lumen of carbon tube step by step, We can obtain stable nitrite accumulation. Subsequently, the reactor was reinoculated with Anammox biomass to construct a quite stable biofilm system for completely autotrophic N removal. After 120 d of operation, 88.7% of NH4(+) -N removal rate, 48.65 mg/L of average TN in the effluent, 83.77% of maximal TN removal efficiency was achieved under the following conditions: air pressure of 0.015 MPa, HRT of 6 h, and influent NH4(+) -N of 200 mg/L +/- 10 mg/L.