To predict pressure drop of ice slurry flow in horizontal pipes, a mixture CFD model was applied to simulate the two-phase flow without considering ice melting. Based on the specific flow features, the Newtonian and non-Newtonian rheological expressions were employed respectively. It is found that in high speed the Thomas viscosity equation behaves well in representing the mixture fluid viscosity; whereas in low speed the Bingham model is more suitable for describing the mixture fluid rheology. Compared with the published pressure drop correlations, the current numerical model can involve with various factors and has a good balance between precision and suitability. The results of numerical model are in excellent agreement with the experimental data and the relative errors are limited to ±15%.