The separation process of multi-particles of coal in a liquid-solid fluidized bed separator (LSFBS) was simulated with various viscous models, including Reynolds stress (RSM), RNG k-e, SST k-w, Std k-e, Std k-w, S-A and laminar (Lam) models, to examine their application performances in simulation of flow field in LSFBS. The predicted separation results of the partition rate of multi-particles with different densities in the heavy product with these viscous models were obviously different from each other. Specifically, the root-mean-square error (RMSE) of the predicted separation result of RSM, compared with the experimental results, was the smallest, being 2.21. Among the viscous models, Lam gave a most inaccurate result, with a RMSE of 5.96. However, RNG k-e model was the most accurate among the five eddy viscosity models, its RMSE was 2.46. On the whole, the accuracy of these viscous models followed the order of RSM > RNG k-e > SST k-w > Std k-e > Std k-w > S-A>Lam.