In order to compare the difference of Na OH/Urea(NU) method and sulfuric acid method in determining the lignin content in tobacco, the lignin content in the tobacco stems and leaves sampled from Guangdong, Sichuan, Hunan, Yunnan and Guizhou were determined by both methods, and the removal rate of interfering substances in pretreatment process and the changes of content and structure of lignin in acid hydrolysis process were compared. The results showed that: 1)The pretreatment of NU method was more efficien...