Abstract: Dynamic settling experiments were carried out assisted with static settling experiments to improve the thickening performance of Benxi Beiying iron tailings. The static optimizing experiments of flocculant were firstly carried out to explore the effects of flocculant type, aging time, and mass concentration of flocculant on flocculation settling performance, taking the height of clear layer, settling rate and solid mass concentration as indicators. Then experiments in the dynamic thickening device were carried out to investigate the effect of mass concentration of slurries, feed rate and dosing rate of flocculant on the flocculation settling under the continuous feed of slurries and flocculant. The accumulation rate, solid mass in the overflow and mass concentration of the underflow were used to evaluate the above experiments. Results shows that the cationic polyacrylamide (PAM) with aging time of 24 h and mass concentration of 0.3‰ had better flocculation performance than the on-site flocculant in the static settling experiment. At the 3 min of static settling experiments, the settling of tailings tended to stabilize. In this case, the height of clear layer was 42 mm, the settling rate was 0.03 mm/min and the solid mass concentration was 70.24%. The iron tailings achieved best dynamic settling effect, when the feed concentration of slurries was 14%, the feeding rate was 0.4 L/min, and the dosing rate was 12 mL/min. In this case, the solid mass in the overflow was 279 mg/L and the mass concentration of the underflow was 68.05%. Under the same conditions, the dynamic settling effect in the plant site was poor, with the solid mass of 282 mg/L in the overflow and the mass concentration of 62.32% of the underflow.