We examined the interactive effects of elevated CO₂ concentration and water stress on the stomatal density, stomatal opening, and stomatal distribution pattern of green pepper with environmental growth chambers, whereby the CO₂ concentration was automatically controlled at 400 μmol mol^-1 (a[CO₂]) or 800 μmol mol^-1 (e[CO₂]). Soil water was treated with full irrigation (75-85% field capacity), mild stress (65-75% field capacity), moderate stress (55-65% field capacity), and severe stress (45-55% field capacity). We found that e[CO₂] increased the stomatal density by 65% and 79% on the abaxial and adaxial surfaces, when green pepper plants were treated with mild water stress at the anthesis stage. Water stress obviously changed the stomatal density (SD) at both the early anthesis and maturation stages, whereas had little effect on the SD at the anthesis stage. Moreover, water stress also altered the stomatal aperture size and shape at the early anthesis stage. As a result, e[CO₂] and water stress not only changed the SD at the early anthesis and anthesis stages, but also modified the stomatal opening at the maturation stage. In addition, elevated CO₂ concentration and water stress made the distribution of stomata more regular on green pepper leaves. Our results indicated that green pepper responds e[CO₂] and water stress not only through modifying the morphology of individual stoma, but also by adjusting stomatal distribution pattern on leaves.