Straw resource was tremendous, however it was utilized poorly. So the research of physical, chemical and mechanical pulping properties of tobacco stalk fiber laid the foundation for utilization of tobacco stalk. Morphology of tobacco stalk fiber was determined by Feica microscope, the length, width and length to wide ratio were analyzed by SPSS 17.0. Chemical composition changes of tobacco stalk fiber after mechanical process were analyzed by applying Block test method with Design-expert 6.0.10.The result present that composition of fiber had significant difference. Hemi-cellulose increased by 3.24%, cellulose increased by 9.62%, lignin increased by 2.52%. Beating degree was positively correlated with the pulping time, beating time and wet weight were a negative correlation. Strength of tobacco stalk fiber was positively with the gramme, and strength was 17 N when gramme was 60 g/m2.