In order to further reduce the pollutant concentration of exhaust gas from cremators, the emission characteristics of pollutants were analyzed, and the effect of cremation duration on the concentrations of pollutants was studied through experiments. The results show that the combustion process in the cremator was affected by many factors. The parameters fluctuate greatly and the combustion stability is poor. Thus the pollutant concentration of exhaust gas fluctuates greatly. For the conventional purification process,the concentrations of dust, SO2, HCl, Hg, blackness and dioxin can meet the requirements of the emission standard of air pollutants for crematory (GB 13801—2015) by extending the incineration time and optimizing combustion conditions of the cremator. When the cremation duration was more than 45 min, the pollutant concentration of exhaust gas are well controlled, and the concentrations of SO2, NOx and CO are reduced to 8 140, and 71 mg/m3.