Abstract: In order to carry out three-dimensional characterization and quantification of the meso-structure of compacted area in total tailings thickening，micro-CT is used to scan the compacted area.Based on volume rendering method，the three-dimensional reconstruction of flocs and pores structure is carried out，and the variation law of parameters such as fractal dimension of flocs， floc area ratio，pore branching distribution，pore size and pore connectivity density are studied.The results indicated that:①volume of the flocs in the compacted area accounts for a large proportion，and the floc connectivity is very good，the floc area ratio is contrary to the change trend of fractal dimension of flocs；②the majority of the pores have no more than two branches，and length of the branches is mostly short；③there are many pore structures in the compacted area，but the pore size is relatively small，the volume of pores less than 500 μm³ accounts for 98.6%，and the surface area of pores less than 500 μm² accounts for 97.6%，the connectivity of pore structure is not good，and the highest connectivity density is 0.000 218. Through three-dimensional reconstruction of the floc and pore structure in the compacted area，as well as the analysis of the structural parameters of the pores and flocs，it is helpful to reveal the law of the mesostructure of compacted area in total tailings thickening.

Key words: Thickening of tailings, CT scan, 3D reconstruction, Pore, Floc