[Purposes] This study aims to establish an evaluation model that comprehensively reflects the morphological characteristics of internal structural cracks and their impact on road bearing capacity. [Methods] A combined subjective-objective method was adopted to construct a morphological characteristic evaluation model based on crack geometric dimensions and a bearing capacity evaluation model based on deflection basin data. Firstly, a three-dimensional pavement model containing structural cracks with different geometric features (width, length, reflection depth) was established using the finite element software ABAQUS. The falling weight deflectometer (FWD) test was simulated to obtain the surface deflection basin and calculate the modified structural strength coefficient (ISSR'). Secondly, the correlation between ISSR' and crack geometric characteristic was analyzed, and regression models were established. [Findings] According to the numerical simulation results, crack width shows no significant correlation with ISSR', while crack length and ISSR' approximately follow an exponential function relationship, and the crack reflection depth and ISSR' approximately conform to an S-shaped function relationship. Based on these functional relationships, the weights of each indicator are determined by quantifying the overlapping degree of geometric characterization by both the morphological and bearing capacity models. Ultimately, a comprehensive evaluation model for internal cracks is formed, which integrates morphological characteristics and structural bearing capacity. [Conclusions] The established comprehensive evaluation model enables the quantitative evaluation of internal structural cracks in semi-rigid base asphalt pavements and addresses the deficiency in the current standard in this aspect, thus providing a theoretical basis and methodological support for structural performance-based preventive pavement maintenance decision-making.