<p>In order to study the transient boundary layer effect in the initial stage of paste slurry pipeline transportation, the transient simulation of paste slurry pipeline transportation was carried out using ANSYS fluent. The distribution and evolution law of each phase volume fraction near the inlet of the pipeline was monitored. Through rheological testing, the evolution law of rheological parameters of paste slurry near the pipeline inlet was obtained, and then the transient boundary layer effect was explored. The results show that, in the initial stage of pipeline transportation, the water phase migrates to the pipe wall, the coarse particle phase moves to the pipe axis, and the fine particle phase accumulates in the velocity ladder area. In the radial direction, the yield stress and plastic viscosity increase in a parabolic manner, while, in the axial direction, they evolve in a negative exponential manner; The prediction models of spatial transient yield stress and plastic viscosity have been constructed, as have the functional relationship between the radius of flow core and pipeline transportation time. A method for estimating the transient boundary layer thickness of paste slurry in the initial stage of pipeline transportation is proposed.</p>