Lots of studies and researches had focused on the calculation of water hammer pressure phenomenon of single-phase for a pipeline of uniform characteristics, but the less work had addressed on the calculation of slurry water hammer pressure in complex pipelines with slurry flows carrying solid particles. In this paper, according to the characteristics of solid-liquid flow, continuity equation and momentum equation of pseudo-homogeneous flow was presented, and a pseudo-homogeneous water hammer model was built based on the characteristic line method. The characteristics of solid-liquid flow's viscosity, resistance and wave velocity was considered in the model. Through the numerical simulation and analysis of transient process of a long-distance slurry transportation pipeline system, the protective properties of accumulator was presented and discussed. The result shows that the accumulator works well while pumping accident happens, and the accumulator can be an effective protection measure of long-distance slurry transportation pipelines.