To achieve accurate and rapid interpretation of in-situ soil mechanical parameters and quantitatively evaluate military equipment mobility， an inversion method for soil Mohr-Coulomb parameters is established based on the dynamic cavity expansion model using the resistance-velocity relationship， acceleration and velocity curves， and the relationship between depth and initial velocity measured during the impact penetration process. It indicates that accurate fitting of the resistance coefficients is critical for interpreting Mohr-Coulomb parameters. Precise results could be derived using the measured velocity curve. Based on the experimental results reported by Forrestal et al. using the proposed method， the relative errors of soil cohesion and internal friction angle interpretation are 2.14% and 9.77%， respectively. Furthermore， the solution domain of the Mohr-Coulomb parameters under the dynamic cavity expansion model is revealed， and parameter sensitivity is investigated. The proposed inversion method resolves the problems of unclear physical images and strong parameter dependency in traditional semi-empirical interpretation methods. It could provide a new approach for rapidly determining soil Mohr-Coulomb parameters and assessing soil bearing capacity in complex geological environments.