Abstract: Objective To study the clinical characteristics of mercury poisoning via different exposure routes. Methods According to exposure pathway,33 patients with mercury poisoning were mainly divided into three groups,namely the inhalational, the digestive and the dermal groups and their clinical features were analyzed. Results The patients due to inhalation exposure had more prominent respiratory symptom and higher urinary level of mercury. Some patients had difficulty in breathing. The urinary level of mercury of the inhalational group was 18.5 and 9.5 times higher than the digestive and the dermal group respectively before the treatment. The urinary mercury of the inhalational group was as high as 5 838.2 μg/gCr. They received averagely 3.91 courses of treatment and 58.3% cases were treated for more than 5 courses. The patients due to digestive exposure had acute onset with typical gastrointestinal symptoms. They were treated averagely for 1.56 courses while 55.56% were cases treated for only 1 course. The patients due to dermal exposure had mostly kidney damage and then diagnosed as sub-acute poisoning. They were treated averagely for 2.25 course and 50% cases were treated for more than 5 courses.The courses among those three groups had Statistical difference (F=8.98,P<0.05). Conclusion The patients of mercury poisoning due to different exposure ways had varied clinical manifestation. The diagnosis and treatment should be specified to achieve early diagnosis and treatment,and reduce sequela and mortality.