The asphalt mixture mesoscopic model is mainly composed of aggregates, asphalt mortar, and the aggregate-asphalt interface layers. Based on Python, the built-in scripting language of ABAQUS finite element software, this paper provides a secondary development of the model to achieve modeling of random aggregate structure and asphalt mixture mesostructure. To solve the problem of aggregate interference, this paper compiles the vector operation of the GIS (Geographic Information Systems) algorithm with Python and applies it to eliminate the problem of aggregate location conflicts and overlaps. Based on the mesoscopic model, this paper simulates the splitting test of asphalt concrete by inserting cohesive units at the interface between aggregates and asphalt and between asphalt units, and the test results match with the actual test results and the simulation results of other scholars, which illustrates the reliability of the asphalt mixture mesoscopic model generated by this method.