In order to quantitatively evaluate the effect of flocculants and the law of floc pore structure change, fractal theory was introduced, and the fractal dimensions of four flocculants, ZYD, JYC-1, JYC-2 and ZYZ, were calculated. The pore structures inside different flocculants were analyzed by using three-dimensional reconstruction and CT slices, and the mechanism of tailing sand flocculation and sedimentation was revealed. The optimal flocculant process parameters were determined by carrying out flocculant process parameter optimization tests.The results show that: ZYZ-type flocculant has the largest fractal dimension, DZYZ=1.8423, with the best flocculation and settling effect.ZYZ-type flocculant forms flocs with larger size, faster settling speed, and forms a better water-conducting channel, with significant thickening effect. Through the multi-parameter and dynamic flocculation test, the slurry concentration of 20% and the flocculant unit consumption of 20g/t were determined as the best flocculation process parameters, and the time of the mud layer height to be settled was calculated to be 731min if the concentration of tailing sand underflow was to reach 70%, and the on-site industrial application was carried out, with good filling effect.