The gas-solid two-phase flow in 90o bending duct of the ventilation and dust removal pipeline was simulated using CFD-DPM, and the erosion rate of the bending duct by anthracite coal particle was calculated, and the influence of the bend diameter R/D ratio of the bending duct, inlet gas velocity, particle size and the materials properties of the duct wall on the erosion was also analyzed. And, the results of numerical simulation were compared with those of experiment and by empirical formula in the literature. The results show that the numerical simulation results match the experimental data and empirical formula calculation values, which indicates that the numerical simulation results are probably credible. When the inlet gas velocity and the particle size are fixed, the erosion rate of the bending duct decreases first and then increases with increasing R/D. When R/D is 3~4, the erosion rate is relatively small, the relational expression between the erosion rate and the inlet gas velocity is E=KV1.08~1.32 when the bend diameter ratio is constant, and the inlet gas velocity is 0~5 m/s, the change of the erosion rate with the inlet gas velocity is small, but when the inlet gas velocity is greater than 5 m/s, the trend is opposite. The relational expression between the erosion rate and the particle size is E=Kdp2.38~3.01. The smaller the bend diameter ratio, the more obvious the erosion rate changes with the dust particle size. And when the dust particle size is smaller than 5 mm, the erosion rate is almost zero. In addition, the materials properties of the duct wall (such as brinell hardness) also influence the erosion rate, and the erosion rate of the material with the great brinell hardness is lower than that of the material with the small brinell hardness.