[目的]分析长安区一家六口自驾游突发一氧化碳(CO)中毒的原因,以减少类似事件的发生。[方法]流行病学调查分析、卫生学调查及现场检测。[结果]共有6名中毒患者,临床症状基本符合CO中毒表现,住院治疗1~2 d后均痊愈出院。现场查看,发现患者驾驶的是经改装的汽车,尾气管未伸出车身外,又略高于车壳下缘。经检测,患者驾驶的汽车发动后10 min,车内CO浓度达132.5 mg/m3。[结论]该事件为一起汽车改装不当引起的急性CO中毒,建议公众选择正规有资质的改装厂改装汽车。 [Objective] To analyze the causes of sudden carbon monoxide (CO) poisoning in a family of six traveling by car in Chang’an District to reduce the occurrence of similar incidents. [Method] Epidemiological investigation and analysis, hygiene investigation and field test. [Results] A total of 6 poisoning patients, the clinical symptoms basically consistent with CO poisoning performance, hospitalized 1 ~ 2 d were cured and discharged. Site inspection and found that patients were driving a modified car, tail pipe did not reach out of the car body, but also slightly higher than the lower edge of the car shell. After testing, patients driving the car 10 min after the launch, the car CO concentration of 132.5 mg / m3. [Conclusion] The incident was caused by an acute CO poisoning caused by improper car modification. It is suggested that the public choose a regular and qualified conversion factory to modify the car.