In order to deal with the serious problem of siltation in the main channel of the Yellow River Diversion Irrigation Area in Zuncun Village, Shanxi Province, a field water and sediment test was carried out on the main channel. The distribution law of suspended sediment in the channel, the relationship between channel flow and sediment deposition, and the sediment carrying capacity of the channel flow were explored by using the vertical suspension index and the planning solution method, so that it could express the sediment carrying capacity of the flow within a certain range. The critical suspended flow corresponding to the channel particle size was put forward. It was beneficial to prevent siltation by adjusting the flow according to the working conditions and particle size. The sediment carrying capacity formula was optimized. The conclusions are as follows: When the diversion flow is 4.46-24.52 m³/s, the sediment content in the channel is between 0.9-4.0 kg/m³, and the sediment content is positively correlated with the flow velocity. The channel flow can be properly adjusted to more than 39.6 m³/s to effectively suspend the sediment with large particle size. The correlation between the optimized sediment carrying capacity formula and the measured value of the main channel sediment reaches 0.828, which indicates that this formula can reflect the current sediment concentration to a high degree, and provide support for the design and analysis of the balance of channel erosion and deposition in the later stage.