Abstract: With the growth of energy demand and the heightened awareness of environmental protection, the efficient and clean utilization of low-quality coal has become a research hotspot. Flotation deashing technology was employed to upgrade and reduce the ash content of two types of low-quality coal from Southwest Shandong Province, with a systematic evaluation of the combustion performance and pollutant emission patterns of the coal before and after treatment. Initially, the upgrading and deashing process significantly reduced the ash content of the coal, with the ash content of low-quality coal 1 and low-quality coal 2 being reduced to 9.23% and 6.97%, respectively, achieving deashing rates of 84.01% and 77.75%, respectively. Concurrently, the sulfur content was reduced from 5.46% and 5.30% to 1.80% and 3.00%, respectively, effectively decreasing emissions of SO₂. Calorific value analysis indicated that the calorific values of low-quality coal 1 and low-quality coal 2 were increased to 30.47 and 32.00 MJ/kg, respectively, which corresponds to an enhancement of 2.70 times and 1.43 times, respectively. Evaluation of combustion behavior revealed that the low-quality coals have higher volatile matter and organic matter content, leading to greater weight loss during combustion; in contrast, the low-quality coals have lower volatile matter content and a slower rate of weight loss during combustion. Pollutant emission pattern research demonstrated that the emission concentrations of SO₂ and NO_x during coal combustion were significantly reduced after flotation desulfurization treatment. The study provides a theoretical basis for the clean utilization of low-quality coal and highlights the potential of flotation deashing technology in reducing pollutant emissions.