Abstract: Solid-phase heterotrophic denitrification and sulfur autotrophic denitrification were successfully coupled in Hybrid Anaerobic Baffled Reactor (HABR) system without adding traditional carbon source. The sawdust and sulfur granules were filled in two systems of HABR respectively as the reactive medium for the removal of nitrate in raw water. In continuous operation, the effluent of the first system was treated by the second system while alkalinity produced by the first system can neutralized the acid produced in the second system. During this process, the water-bath temperature was (25±1)℃ and the NO₃^--N volume loading of raw water varied as 72,0, 96g/(m³·d).The experimental results demonstrated that the removal efficiencies of NO₃^--N was 99.0％without the accumulation of NH₄⁺-N and NO₂^--N. The NO₃^--N removal percentage of each system was 50.0％, while the NO₃^--N volume loading was 96g/(m³·d).The ρ(COD_Mn), ρ(SO₄^2-) of effluent were 5.74-10.05,5-870mg/L. The integrated system had the capacity of pH balance, therefore the limestone for pH adjustment in sulfur autotrophic denitrification was not necessary in this combined process. The influent pH was 7.5, and the effluents of two systems were kept neutral at optimum operation conditions. In general, the HABR integrated system perfectly showed synergy in two aspects:pH balance capacity and integrated denitrification effects. Compared with the conventional biological heterotrophic denitrification, the integrated system reduced costs and enhanced the denitrification efficiency.