For the numerical simulation of solid-liquid two-phase flow in pipe, the conventional CFD approach is using multiphase flow and treating solid particles as a kind of quasi-fluid , but it is hard to describe the characteristics of solid particles such as shape and size, collision, agglomeration and separation. In this paper, therefore, one flange connection and two conventional horizontal pipes with 0.7 m in diameter were selected as research objects. Discrete element software EDEM was coupled with CFD software FLUENT to simulate the solid-liquid two-phase flows and the distribution of particle concentration in the pipes and flange connection. The inlet flow speed was 5.0 m/s. The solid particle density ranged from 1 300 kg/m3 to 2 300 kg/m3. The solid volume rate at pipe inlet was 10%~30% and the diameter ranged from 20 mm to 60 mm. As the results of the simulation, the solidliquid two-phase flows, the trajectories of the solid particle cluster and solid volume rate distributions were obtained in different flange connections due to manufacture and improper installation in practical application.