To analyze the effect of slurry temperature on Ultrafine tailings backfill slurry (UTBS) flow characteristics, a new comprehensive Reynolds number (Rc) model considering slurry temperature for determining the flow pattern of UTBS was proposed. The flow evolution characteristics of UTBS considering the effect of slurry temperature were investigated under the condition of coupled multi-physical fields. UTBS flow velocity field was divided into shear zone and structural flow zone. With the flow proceeded, the area of the structural flow zone decreased. Increasing slurry temperature could generate more gel, which could wrap the tailings particles and reduce the resistance loss. When transport flow increased, the interaction between UTBS particles and friction increased, which caused the resistance loss to increase. Influenced by "non-uniform interference settlement" and the law of tailing sand particle transport, the resistance loss increased with the increase of stowing gradient. This paper suggests that the mine could choose a transport flow rate of 220 m 3 /h and stowing gradient of 5 as a reference for pipeline transport.