In order to reduce the amount of NO3-–N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO2-–N in a single reactor, the preference of S0 for reacting with coexisting NO2-–N and NO3-–N in the sulfur autotrophic denitrifying (SADN) process and the coupling effect of short-cut SADN and the Anammox process were studied. The results showed that S0 preferentially reacted with NO3-to produce NO2-–N, and then reacted with NO2-–N when NO3-–N was insufficient, which could effectively alleviate the competition between SADN bacteria (SADNB) and Anammox bacteria (An AOB) for NO2-–N. After 170 days of operation, coupling between short-cut S0-SADN and the Anammox process was first successfully achieved. SADNB converted the NO3-–N generated by the Anammox process into NO2-–N, which was once again available to An AOB. The total nitrogen removal efficiency eventually stabilized at over 95％, and the effluent NO3-–N was controlled within 10 mg/L, when high NH4+–N wastewater was treated by the Anammox process. Microbial community analysis further showed that Candidatus Brocadia and Thiobacillus were the functional microorganisms for An AOB and SADNB.