Rotary kiln is a high-energy consumption equipment widely used in metallurgy, chemical industry, environmental protection and other fields. As the main energy source of the thermal process of the rotary kiln, the efficiency of fuel combustion is directly related to the energy-saving operation of the rotary kiln. In order to improve the pulverized coal combustion efficiency in the rotary kiln, the pulverized coal combustion process in the rotary kiln was numerically simulated by ANSYS Fluent 19.0 software. By controlling a single variable and designing a multi index orthogonal test condition, the influence and significance of air excess coefficient, pulverized coal particle size, swirl angle, ratio between internal and external air volume on the pulverized coal combustion in the rotary kiln were analyzed. The influence rules of each factor on pulverized coal combustion and optimal working condition were obtained. The results showed that the increase of air excess coefficient and pulverized coal particle size increased the flame length, reduced the flame diameter and make the flame slender. The increase of swirl angle shortened and thickened the flame shape. With the increase of the ratio of internal and external air volume, the flame length first increased and then decreased, and the flame diameter first decreased and then increased. The four factors ranking in a decreasing order of in?uence were the pulverized coal particle size, ratio between internal and external air volume, air excess coefficient, and swirl angle. The optimal operating parameter combination of pulverized coal combustion in rotary kiln were air excess coefficient of 1.1, pulverized coal particle size of 40 μm, swirl angle of 25°, ratio of internal and external air volume of 0.9. Compared with the original working condition, the flame length and flame diameter of the optimized working condition increased respectively by 8.9% and 13.9%.