<p>Electric vehicle (EV) fire accidents have attracted widespread attention in recent years. Particularly, EV fires in underground parking garages may exhibit much higher hazards than those in open spaces owing to the limited space and poor ventilation. However, the fire evolution process and corresponding hazards of EVs parked in underground parking garages are still unclear. In this study, a gasoline in a square oil pan was used to ignite the chassis of EVs in the underground parking garages, and the fire evolution process and characteristics were investigated by analyzing the burning behaviors, temperature variations, thermal radiation, and smoke concentrations. The results show that the fire evolution of EVs adopting blade batteries as the energy source can be divided into three stages: EV body burning, the battery pack and vehicle body co-combustion, and combustion decline. The temperature spread rate of the chassis of EVs can reach 0.0141&#xa0;s^− 1. According to the radiation model, the safe distance for unprotected personnel was 8.7&#xa0;m. In addition, during the EV fire in underground parking garages, the major gases released mainly consist of CO₂, CO, NO, NO₂, NO_x, and SO₂, and asphyxiating gases are less hazardous than irritating gases. This work investigates the evolution and hazards of EV fires in confined spaces, and the results can provide scientific guidance and data for the layout and fire protection strategies of EVs in underground parking garages.</p>