Abstract: In order to find out a method on substitute of different grades ，we analysised the different grades tobacco of middle and southern of He-nan province,including routine chemical components, smoke components and smoking quality. And then use the statistic analysis software SPSS11.0 to defined the usibility of these tobacco leaf in prescription. The result showed :(1) most of the samples have the comparability, only little of these samples exist obvious difference, (2) the quality index in a group have little diference,otherwise difference is obvious.(3) in the process of prescription ,we can use the quality simility to find the substitute when a kind of tobacco leaf in prescription is limited or absence.