The mature landfill leachate was adopted to cultivated anaerobic ammonia oxidation bacteria in the UASB reactor which fed with inorganic wastewater, the running performance of the system was explored in different substrate concentration and hydraulic retention time, the activity inhibition of anaerobic ammonia oxidation by substrate and landfill leachate and the inhibition kinetics were analyzed. The system adapted to the landfill leachate gradually and implement efficient denitrification when the system run 75d. The removal amount of substrate was increased at first and then decreased with the increasement of the substrate concentration. As the extension of HRT, the concentrations of substrate and landfill leachate was increased, the effect of denitrification was decline in system. The thresholds of substrate inhibition were that NH₄⁺-N concentration was 489.03mg/L and NO₂^--N concentration of 192.36mg/L. when NH₄⁺-N was inhibitor, V_{max(NH4⁺-N)} was 0.1893mg/(mg·d), the half-saturation constant was 39.39mg/L, the inhibiting kinetic constant was 3482.27mg/L; when NO₂^--N was inhibitor, V_max(NO2^--N) was 0.246mg/(mg·d), the half-saturation constant was 43.19mg/L, the inhibiting kinetic constant was 701.15mg/L. Anaerobic ammonia oxidation is very susceptible especially by the landfill leachate, the activity of anammox was inhibited completely when the landfill leachate concentration was 1450.69mg/L (which calculated in COD).