Abstract: Serious wear of the movable guide vanes of the hydraulic turbine in the sediment-laden river power station,resulting in violent vibration of the turbine unit,even endangering the safe operation of the unit. In order to reveal the flow characteristics and wear characteristics of the guide vane area under small opening conditions,this paper establishes a three-dimensional water model of the full flow passage of the Wanjiazhai prototype turbine,and DPM model and standard turbulence model was used to simulate the solid-liquid two-phase flow for four small opening conditions. The results show that: the opening degree is reduced from 40% to 10%,the flow in the guide vane channel is gradually deteriorates,and the change gradient of flow velocity and pressure in the guide vane area gradually increase,the pressure difference on both sides of the guide vane vertical sealing position is increased from 48 k Pa to 108 k Pa,and the velocity at the vertical sealing position is increased from 18 m/s to 24 m/s; Under the condition of 10% opening,the flow channel in the guide vane area is narrow,and the sand-laden water flow forms jet wear at the outlet of the movable guide vane,the head and tail of the movable guide vane and the sealing position of the facade are severely worn,with the increase of the guide vane opening,the wear degree and wear area of the movable guide vane surface gradually decrease. This research is of great significance for the scheduling and operation of hydraulic turbines and the wear protection of movable guide vanes in sediment-laden power station.