In order to enhance the comprehensive property of asphalt concrete, waste polypropylene (PP) microplastics were utilized to modify the asphalt matrix, resulting in the preparation of AC-13 asphalt concrete. The study focused on the properties of both asphalt and asphalt concrete. The results show that the addition of microplastics improves the deformation resistance and high-temperature stability of the modified asphalt, as well as enhances the mechanical properties, high temperature stability, low temperature stability, and water stability of the asphalt concrete. With a microplastic content of 4%, compared to the matrix asphalt, the modified asphalt exhibits a 20% reduction in penetration at 25 ℃ and a 12 ℃ increase in softening point. At the same microplastic content of 4%, in comparison to the matrix asphalt concrete, the modified asphalt concrete shows an 11.6% increase in immersion Marshall residual (MS₀) and a 12.8% increase in freeze-thaw splitting tensile strength ratio (TSR), an 86% improvement in dynamic stability, a 67.0% reduction in rut depth, a 14.6% decrease in volume of air voids (VV), a 21.1% increase in Marshall stability (MS), a 7.8% increase in voids filled with asphalt (VFA), and a 35.6% increase in low-temperature bending failure strain.