This study aims to investigate the meso-structural evolution characteristics of porous asphalt mixtures (PAM) under stress and their effects on drainage and noise reduction environmental functions. Digital image processing technique was used to accurately identify the internal voids during uniaxial compression testing. The focus was on analyzing and simulating meso-scale differences in internal void structures before and after deformation and quantifying the evolution of these voids during the strain process. Drainage and noise reduction tests were conducted, and correlation analysis and factor screening were performed. The results indicate that in stress-induced meso-structural evolution, contact between aggregates generates force chains, and with increasing strain, the length of these chains and the number of aggregate contacts increase. Significant forces occur at the interface between aggregates and asphalt mortar. Aggregates undergo relative translational motion due to resistance to loads, resulting in compressed voids, cracks between asphalt mortar and aggregates, and gradual deterioration of the mixture structure. Additionally, the increase of strain significantly reduces the drainage and noise reduction performance of porous asphalt mixtures. The scale relationship diagram between macro- and meso-scale indicators identifies strain, void area and void sphericity as the primary influencing factors. The research findings contribute to understanding the stress transfer characteristics of PAM at the meso-structural scale, thereby enabling adjustments to grading, optimization of void structures, and enhancement of their long-term environmental functions.