To address the issue of coal powder agglomeration and wall adhesion at the perforation in high-yield coalbed methane wells, which leads to blockages and reduced gas production, a model for coal powder agglomeration and adhesion under a thin liquid film was developed, considering the liquid film wrapping around the particles. Using CFD-DEM coupled simulations, a mathematical model for gas-carried liquid film coal powder in the perforation-borehole system was established, and the dynamic behavior of agglomeration and adhesion at different gas flow velocities was studied. The results show that as gas velocity increases, coal powder agglomeration first increases and then decreases, while wall adhesion decreases. When the fluid velocity in the annulus increases from 3 m/s to 5 m/s, the coal powder volume fraction at the perforation increases, agglomeration becomes more pronounced, and more particles settle at the bottom. However, as the velocity increases from 5 m/s to 8 m/s, agglomeration weakens, and fewer particles settle. These findings provide a theoretical basis for optimizing coal powder removal technology in high-yield, stable coalbed methane wells, improving production efficiency and minimizing the impact of coal powder.