Particle size distribution has a great impact on the permeability of burden packed bed in the sintering process, which affects fuel consumption, carbon emission and product quality in industrial production. This study establishes a 1:1 scale DEM model of #2 sinter burden charging system in the Shougang, China. Based on the ternary-sized diagram, two innovative indices, namely segregation degree (SD) and segregation tendency (ST), are proposed to quantitatively evaluate partide size segregation during the charging process. The small-sized particles have lower horizontal velocities on the nine-roller charger than the large ones, therefore they play a major role in the inner granular flow and give priority to forming the upper layer of the packed bed. Compared with the nine-roller's speed, the particle-roller's wall friction coefficient has a greater impact on size segregation, and the large-sized particles show a more significant accumulation at the bottom with the increasing friction coefficient. In addition, the medium-sized particles distribution, especially in the middle part of the packed bed, is not obviously affected. (C) 2018 Elsevier B.V. All rights reserved.