Lignite is difficult to be effectively separated by traditional preparation techniques because of its sliming property and difficulty of subsequent dewatering. A dry separation method of using a pulsing air classifier is applied to decrease the ash content of lignite for improving its effective utilization. The lignite sample used in this study was collected from Inner Mongolia, China. Mineralogical characteristics of the lignite sample were analyzed, and the effects of airflow rate, pulse frequency, and feed rate on the separation efficiency of -6 + 3 and -3 + 1 mm size fractions were determined using the lab pulsing air classifier system. The results demonstrated that the ash content of the product was reduced by 10.18% and 30.98% for the -3 + 1 mm and -6 + 3 mm size fractions, respectively, and the pulsing air classifier has a better separation efficiency for a larger size fraction.