A numerical simulation of the fire characteristics in the A320 cabin was conducted, establishing a full-scale three-dimensional model that comprehensively considered the cabin curvature, seat layout, and ventilation conditions. Through a multi-mesh division scheme and the T2 fire model, the patterns of smoke spread, toxic gas distribution, and visibility changes during an aircraft crash fire were analyzed. The results show that the fire development exhibits distinct stages. The temperature in the cabin ceiling reaches 180 °C at 104 s, and the peak temperature above the fire source reaches 925 °C at 260 s. The CO concentration in the ceiling area reaches 500 ppm at 98 s, and the entire cabin exceeds 500 ppm at 600 s. The CO₂ concentration reaches 1% in the ceiling at 115 s and exceeds 1% throughout the cabin at 600 s. Visibility drops below 5 m at 93 s and remains below 5 m throughout the cabin at 600 s.