<p>Full-scale or field experiments help us understand the mechanics of debris flow. However, they are quite expensive, and performing a parametric analysis is impractical. Numerical modelling is an alternative if the process can be realistically simulated. The dynamic impact coefficient (α) is an important factor to consider when designing debris flow barriers. Currently, only a few numerical modelling methodologies have been reported to investigate the flow and impact kinematics of debris flow barriers. The current work aims to numerically simulate the debris flow and model its impact on the debris flow barriers. The Material Point Method (MPM) was investigated in this study due to its advantages over other approaches. It has been found that the MPM model is consistent with the physical observations acquired from the large flume experiments. Present study indicated that numerical modelling employing the MPM approach serves as an excellent method for analyzing debris flow mechanisms and ascertaining the selection and arrangement of barriers. A systematic parametric study analysis revealed that the dynamic impact coefficient is affected by the material properties of the debris and the rigidity of the barrier. Specifically, the dynamic impact coefficient increased by 61.2% as Young's modulus of the barrier increased from 1 to 25 GPa. Similarly, the frictional angle of the debris was also observed to influence the dynamic impact coefficient, with an increase from 27° to 44° resulting in a 31.4% reduction in dynamic impact coefficient.</p>