The article focuses on the problem of changes in flow capacity caused by channel bottom slopes, and designs a U-shaped channel measurement and control integrated sluice. By combining model experiments and numerical simulations, the flow capacity and corresponding flow patterns of the integrated sluice under different inflow rates, opening degrees, and five different bottom slope conditions are studied. The results show that the water flow in front of the integrated measurement and control sluice is more stable, and the upstream water depth increases with the increase of flow rate, and decreases with the increase of opening and bottom slope. The downstream water surface profile shows an opposite pattern to the upstream when the flow rate and opening change, and the length of the water jump increases significantly when the bottom slope increases. When the inflow rate remains constant, the downstream water depth conforms to the water jump function curve. The threshold for distinguishing dam flow is affected by the bottom slope. The gentler the bottom slope, the smaller the threshold discrimination range, with a minimum value of 0.61. The steeper the bottom slope, the larger the threshold discrimination range, with a maximum value of 0.75. Summarizing the flow formulas under different flow states, the measurement formula for free outflow has a higher correlation coefficient and accuracy, with a relative error of less than 5%, all of which meet the accuracy requirements for water measurement in irrigation channels. The integrated measurement and control sluice proposed in the article can adapt to changes in the bottom slope to achieve the function of integrated measurement and control, while ensuring the accuracy of flow measurement. It can provide reference for the research and application of water measurement facilities in irrigation areas.