Abstract: In order to evaluate the flooding risk of the level crossing of the main stream of the Mihe River, the design flooding process of 50 and 100 years return periods was simulated and calculated by constructing a one- and two-dimensional coupled hydrodynamic mathematical model, and the flooding risk of the Level-crossing was analyzed from the inundation range, average submerged water depth, submerged water depth and proportion of different magnitude, submerged duration, and flow field changes at different times. The calculation results show that there is still a greater risk of flooding if the current Level-crossing is not blocked, the duration of the overflow flood is about 48 h, the depth of the submerged water in the inundation area is mainly less than 0.5 m, and the proportion of the inundation range lasting more than 24 h and above is relatively high. The simulation analysis results can provide decision-making references for future river flood control and bridge reconstruction, and at the same time promote the construction of digital twins in the Mihe River Basin, providing theoretical support for accurate prediction and timely warning of flood risks in the river basin in the future.