Asthma is an important respiratory disease that endangers human health, while its complex mechanisms of pathobiology have not been fully understood. Recently, environmental factors are increasingly recognized to play important roles in the pathogenesis of asthma. In particular, the effect of PM2.5 (particulate matter with diameter smaller than 2.5 μm) on the structure and function of pulmonary airways at cell level has become a research hotspot and frontier, and led to many important findings. In this article, the main pathological features, i.e. airway inflammation and hyperresponsiveness were discussed, and recent progress and important findings in pathological effects of PM2.5 on the airway and its mechanism were reviewed, including PM2.5 transport and deposition in the airway, PM2.5 and airway inflammation and damage, PM2.5 and airway remodeling, PM2.5 and airway hyperresponsiveness, PM2.5 and airway smooth muscle cell mechanics via either indirect regulation or direct interaction. The analysis on the role of PM2.5 in airway biomechanics in relation to asthma pathobiology will provide a valuable reference for studying effects of PM2.5 on the respiratory system.