Aiming at the problem of channel siltation in the water diversion project of rivers with rich sediment, the scale model test of the trapezoidal desilting channel with a swirling flow generato was carried out based on Jingtaichuan Electric Power Irrigation Project, and the distribution law of water and sediment in the channel and sendiment transport pipe under different water and sediment conditions was studied. The results show that the incoming flow conditions have a significant influence on the sediment concentration and particle size distribution in the upstream channel of the sediment transport pipe.The conditions of large particle size, high concentration, high water depth and small flow promote the sedimentation of coarse particles, which makes the sediment concentration in the channel show the distribution characteristics of low surface layer, high middle layer and high bottom layer. The trapezoidal desilting channel with a swirling flow generato can effectively separate large-size sediment from the mainstream. After the sediment transport pipe, the concentration of 0.329 ~ 1.250 mm large-size sediment in the channel decreases significantly, and the distribution of 0.078 ~ 0.329 mm fine particles tends to be uniform. Under the first and second conditions, the relative reduction rates of large particle size sediment volume are 52.72% and 49.91% respectively; When the imported sediment content increased from 4.63 kg/m3 to 6.70 kg/m3, the relative reduction rate gradually increased by 39.26%, 50.93% and 60.72%, respectively; When the flow rate increased from 2.645 m3/s to 4.383 m3/s, the relative reduction rate gradually decreased by 65.64%, 50.93% and 32.22%, When the water depth increased from 80 cm to 120 cm, the relative decrease increased first and then decreased by 49.91%, 74.47% and 54.69% respectively. The proportion of coarse particles in the sediment transport pipe increases with the increase of inlet concentration, particle size and water depth, but decreases with the increase of flow rate. Under various working conditions, the sediment deposition thickness of the trapezoidal desilting channel with a swirling flow generato channel decreased by 37.26% ~ 70.68%, the sediment patterns were mostly stripe-shaped, and the proportion of 0.616~1.250 mm particles in the sediment body decreased significantly. The results can provide theoretical basis for the design of the trapezoidal desilting channel with a swirling flow generato channel.