In this work, the characteristics of the maldistribution phenomenon in a symmetrical dual-side refeed circulating fluidized bed is numerically studied. The influence of maldistribution on the performance of different sections is discussed. The results show that the maldistribution lowers the total performance of parallel cyclones and the L-valve has a self-balancing to lower the degree of maldistribution. Moreover, the effects of gas inlet velocity, total solid inventory and wall function on the degree of maldistribution are explored. The simulation results confirm that the maldistribution can be captured in the system. The degree of the maldistribution in parallel external loops decreases with the increase of gas inlet velocity and total solid inventory; however, it is not sensitive to the wall roughness. This work provides insight of the cause of gas-solid maldistribution and the influence of different operation conditions on the degree of maldistribution. (C) 2020 Elsevier B.V. All rights reserved.