Abstract: With the constantimproving requisition of flue gas pollutants emission in thermal power plants, the low-nitrogen( low-NO_x) combustion technology is used in circulating fluidized bed(CFB) boilers to reduce the generation of NOx during the combustion phase. However,withthe use of the low-NOx combustion technology,the oxygen content in the local atmosphere especially in the dense phase zone decreases by 1% to 4%,and the reducing atmosphere such as CO increases by 1% to 2%. Desulfurizationreaction can show different reaction paths under different oxygen concentrations and reducing atmosphere conditions,which will affect the rate of overall sulfurfixing rate and the generation of different sulfur-fixing products,leading to the difference of the final sulfur fixation rate. Therefore,the low nitrogen combustion condition in the furnace definitively willimpact the process of calcium basedsulfur fixation.In order to clarify the influence of the low-NOxcondition on the calcium-based sulfur fixation in furnace and decrease the SO_2 and NOx emission at the same time,thus realize the coupling of low-NOxcombustion technology and calcium-based sulfur-fixing technology in CFB boiler,The influence of low nitrogen combustion reaction conditions on the calcium based sulfur fixation process in CFB boiler was reviewed in this paper.. The effects of reducing atmosphere and oxidation-reduction alternating atmosphere conditions on the calcination of sulfur-fixing agent,desulfurization and the decomposition and transformation of sulfur-fixing products were described respectively. The results show that thechange of CO_2 concentration has anadverse effect on the calcination of CaCO_3. The partial pressure of CO_2 in the atmosphere will directly weaken the degree of calcination reaction. However,there are no reports about the influence of the O_2 and CO concentration change on the CaCO_3 calcination.Theoretically,it could be inferred that it scarcely has effect on the calcination,but it needs further experimental proof. The current researchresults show that the process of sulfur fixation in the furnace is complicated under the oxidation-reduction alternating atmosphere.As the oxygen disappearing,the sulfur fixation rate decreases by about 20%. With the increase of CO concentration in the reducing atmosphere,the sulfur fixation rate further decreases.With the enhancement of reducing atmospheres such as CO content,the stability and decomposition temperature of the sulfur-fixing product CaSO_4 decreases,while the stability of CaS increases. When the atmosphere and temperature conditions are reasonably controlled to form sulfur-fixing products with CaS as the core and CaSO_4 as the shell,the calcium utilization rate and sulfur-fixing efficiency can be improved. In conclusion,the influence of the low-NOx condition on the desulfurization process is not deterministic. Meanwhile,due to the complexity of sulfurization reaction and the instability of sulfur fixing products,so far,there is no optimum operation condition suggestion about the best matching of different sulfur fixation agents with reaction temperature and reaction atmosphere. Therefore,it is necessary to further explore the sulfur fixation reaction mechanism of calcium based sulfur fixation agents such as limestone and carbide slag in different oxygen concentration atmosphere and reducing atmosphere to clarify the influence of low nitrogen combustion conditions on calcium based sulfur fixation process,and finally the ideal operating suggestion for the combination of low-NOx combustion and calcium-based sulfur fixation in furnace is obtained,which would provide a reliable theoretical basis for actual production.