Abstract: Abstract: The fire protection design of subway underground parking lot is difficult because of the uncovered scope in the current code, and the fire protection lane design is the main difficulty. Taking a specific project as an example, this paper puts forward a fire-fighting design idea for subway underground car-park: the fire-fighting design of underground parking lot should be separately carried out according to the throat area, the track area of train-washing line, the area of fire lane, the area of large reservoir and the area of single unit outside the large reservoir, besides, the annular fire lane can be regarded as the transition safety zone if the opening ratio of roof and the number and spacing of safety exits are satisfied.

Key words: Key words: metro underground parking lot, fire protection design, fire lane, opening ratio