Abstract: Cement paste backfill (CPB) technology is a key method for mine waste treatment, and pipeline transport is critical for safe and efficient waste transfer. Variations in raw material properties can cause slurry segregation, increase pipeline wear and resistance, raise the risk of blockages or bursts, and disrupt operations. To study CPB slurry segregation during transport, CPB was prepared using cement as the cementitious material and unclassified tailings as inert materials. A small annular-tube device using an electrical resistance tomography system was developed to analyze its flow characteristics, and quantitative segregation assessment methods were developed. The results indicated that CPB conductivity increases with transport time but decreases with higher solid mass content, with the latter having a greater impact. At a low solid content, solid particles migrated toward the bottom of the pipe as the flow time increased, and the migratory behavior of the particles diminished as the solid content increased. At a flow rate of 1.25 m/s, the heterogeneity index for CPB with 58wt% solid content increased by 1.24 in 20 min, whereas that for CPB with 62wt% solid content increased by 2.17. Higher solid mass content amplifies the effect of conveying time on segregation, emphasizing the need to balance these factors for minimizing segregation. These insights can guide the optimization of mine pipeline transport systems.