In view of the issue that the total particulate matter emission during the environmental protection acceptance of a biomass boiler exceeded the amount predicted in the environmental impact assessment (EIA) report, the abnorma lindicators such as the flue gas volume, oxygen content, and flue gas temperature were analyzed, as well as the reason why the particulate matter emission exceeding the standards. The results show that over-standard particulate matter emission is caused by excessive design air volume of the dust removal system, imcomplete combustion of fuel, excessive content of oxygen and flue gas, and too high flue gas temperature. It is recommended to optimize design, adjust wind speed, standardize data analysis and strengthen technical consultation.