The invention discloses a synergic denitrification technology of heterotrophic nitrification and aerobic denitrification bacteria and ammonia oxidizing bacteria. The synergic denitrification technology is characterized in that organic carbon and part of ammonia nitrogen in domestic sewage are removed through the heterotrophic nitrification and aerobic denitrification bacteria, and the purpose of removing the ammonia nitrogen and the organ carbon in the domestic sewage is achieved by the aid of the advantage of promoting growth of the ammonia oxidizing bacteria through an intermediate reaction product-hydroxylamine and converting the rest of the ammonia nitrogen in the domestic sewage into nitrite nitrogen through the ammonia oxidizing bacteria. A biofilm culturing method is adopted in the technology, a granular structure that the ammonia oxidizing bacteria is wrapped through the heterotrophic nitrification and aerobic denitrification bacteria is formed to promote the synergic effect of two bacteria, denitrification reaction by additionally adding carbon source is not needed, simpleness in the process is achieved, and the organ carbon and the ammonia nitrogen in the domestic sewage are effectively removed.