An emergency rescue station in a railway tunnel is taken as an example to study the layout scheme of jet fans, analyze the influencing factors and rationally simplify fire ventilation calculation. The fire ventilation calculation model is established by software subway environment simulation (SES); and then three fire ventilation schemes, i. e. jet fans in tunnels, those in cross passages and those in tunnels and cross passages, are compared and selected; finally, the influencing rules of natural wind, fire location, fire scale and tunnel longitudinal slope on fire ventilation are studied respectively and comprehensively. The study results show that: 1) For separated tunnels, the jet fans arranged in main tunnels in front and at end of rescue station is the best choice for minimum fan needed. 2) All the abovementioned factors have influence on wind speed at protection door; and the influencing degree of the natural wind is the largest, followed by fire location, fire scale and tunnel longitudinal slope. 3) The number of fans needed under the most unfavourable conditions of natural wind and fire conditions is 1.9 times that without consideration of influencing factor.