In determining and analysis of the lung function for 51 civil pilots, among them 31 are smokers, average smoking index is 31820pcs/year, average flying time 13, 000 hours. Determination result: smoking group FEF 25- 75%, FEF 50%, FEF 75% with non-smoking group is comparatively lower and has statistical meaning. Non-smoking group in the above index shows 32.4% abnormal rate, which is higher than normal people. The result explains: for smoking civil pilots, it mainly affects their respiratory duct, second hard smokers for nonsmoking civil pilots has much greater effects.