Civil aircraft water waste system is an important system to ensure comfort and personal hygiene，and research on gas-liquid-solid three-phase flow characteristics of water waste system pipeline is one of the key technologies.This paper takes the civil aircraft water waste system as the research object.We used the CFD-DEM model to simulate the gas-liquid-solid three-phase flow process of water waste system. We analyzed the flow pattern and flow characteristics of the gas-liquid-solid three-phase of the water waste system pipeline, and obtained the flow time of the liquid phase and the solid phase. The results show that the solid phase and the liquid phase flow in the wastewater pipeline in an adherent spiral along the moving direction, and the greater the turbulent energy in the region with high gas velocity, so the gas phase motion is dominant for gas-liquid-solid three-phase flow; the average cross-section velocity is the largest in gas phase, the second in the liquid phase and the smallest in solid phase; the static pressure of the system continuously decreases along the axial direction of the pipeline, and the total pressure loss decreases with time.Through the analysis of the flow performance of civil aircraft wastewater system, this paper provides design input for the design of wastewater system, which has guiding significance.