Preventing lost circulation during coalbed methane drilling is a challenging issue that needs to be addressed urgently. To deepen our understanding of the plugging mechanism of fractured formations and improve coalbed methane drilling efficiency, a lost circulation plugging model suitable for fractured coalbed methane formations was established based on CFD-DEM fluid-structure coupling theory. Simulations and experimental validation were conducted, and the effects of different lost circulation materials with different particle sizes, concentrations, gradations, and particle shapes on plugging efficiency were systematically analyzed. The results show that: ① The bridging efficiency of plugging particles within fractures is crucial for overall plugging efficiency; ② Both particle size and concentration have critical thresholds; below these thresholds, plugging is impossible, while above these thresholds, efficiency gains are limited. Furthermore, when the concentration exceeds 20%, the plugging efficiency improves by less than 1%, while increasing drilling fluid viscosity and cost; ③ Under conditions where large particles form a stable framework, [ ]filling the bridging gaps with small particles significantly reduces the permeability of the plugged layer. Specifically, replacing 3% of the plugging particles by a fraction of their original size with particles a quarter of their original size reduces the leakage rate by 96.2% and increases the bulk density by 21.6%. This study quantitatively reveals the influence of plugging particle properties on fracture plugging performance, providing a theoretical basis and technical support for preventing and controlling lost circulation in coalbed methane drilling.