Abstract: To explore the sediment deposition characteristics in pressurized pipelines and impacts of sediment introduction on the hydraulic characteristics, a pipeline model based on Yanhuanding water transmission project was taken as an example, and the numerical simulation method was adopted in combination with experimental observation.The results showed that the mathematical model used in the simulation was basically consistent with the experimental observation data and theoretical calculation values, and has good suitability.The sediment at the bottom of the pipeline rising section was distributed in a concentrated accumulation pattern under high flow rates, and in an intermittent pattern under low flow rates.While the sediment at the bottom of the descending section exhibited intermittent distribution characteristics when the flow rate and slope were small, and showed a band shaped distribution when the flow rate and slope increased.Before the sediment passed through the rising section, the sediment accumulation in the small slope of the descending section was inversely proportional to the flow rate, while the sediment accumulation in the steep slope and horizontal section of the descending section was directly proportional to the flow rate.The critical non-silting velocity of sediment in the pipeline was proportional to the particle size of the sediment.The water level difference between the upstream and downstream of the pipeline increased after the introduction of sediment, and the range was between 0.43～2.27 cm.After the introduction of sediment, the velocity of pipeline section decreased slightly, with a maximum decrease of 0.045 m/s, and the peak velocity in a pipeline section shifted upward when sediment was mixed.The pressure at each section remained basically unchanged under clear water and water sand conditions, with a maximum difference of only 0.46%.