Abstract: A 2D axisymmetric mathematical model was developed for an O₂ generator and the protective performance of the O₂ generator was simulated. The model's rationality was verified by experiments under typical operational conditions. Then, the influ-ences of labor intensity, inlet CO₂ volume faction, equivalent diameter of oxygen-generating particles, and pipe diameter at the entrance on the protective performance of the O₂ generator were studied by the model. The simulated results show that both labor inten-sity and inlet CO₂ volume faction have significant effect on the protective performance of the O₂ generator. A higher labor intensity and a higher inlet CO₂ volume faction share the same trend, which means a much shorter protective time and a much higher outlet peak temperature. The protective time decreases with increasing equivalent diameter of oxygen-generating particles, exhibiting an approxi-mately negative liner relationship. The protective time for 12 mm particles is 32.15 min shorter than that for 6 mm particles. However, larger particles will lead to a lower outlet peak temperature. Different from the front three factors, pipe diameter at the entrance has limited effect on both the protective time and outlet temperature.