Abstract: From 2004-2006,tobacco root-stem disease survey pathogen isolation were carried out in Yunnan province.In Wenshan prefecture the marjor tobacco plant county,such as wenshan,Yanshan,Guangnan,Xichou and Malipo county.The results showed that the damping off was main was main in the seedling;the tobacco bacterial wilt was main in the rosette stage and in the mature stage.Much plant mixed efffet bacterial wilt and black shank.20% plant mixed effect bacterial wilt and hollow stalk.