This paper is aimed at qualitative giving up smoking dynamic on adolescent. A basic
mathematical model, which is a slight refinement of the model presented in [F. Brauer, C.
Castillo-Chavez. Mathematical Models in Population Biology and Epidemiology. Text in
Applied Mathematics. Springer, 2000; G.C. Castillo, S.G. Jordan, A.H. Rodriguez.
Mathematical models for the dynamics of tobacco use, recovery and relapse. Technical Report
Series, BU-1505-M. Department of Biometrics, Cornell University. 2000] is designed first of
all. This paper (based on) subdividing the total population in the middle and high school into
non-smoking, smokers, which are divided into each two subclasses; FTND scores of zero point
to four point indicating severe nicotine dependence and FTND scores of five point to ten point
indicating severe nicotine dependence, quit temporarily and quit permanently, which is one
possible extension of the susceptible-infective-removed(SIR) type epidemic model. It is
assumed that non-smoker never has been smoking and temporary smokers may become
smoker again or permanent smokers and permanent smokers once quit never smoking in the
entire life span and is defined as more than 6month stopping smoker by WHO. The existence
and stability of the smoking-free equilibria and positive equilibria of the model are examined
in terms of a certain threshold condition R0, the smoking generation number(the basic
reproduction number), is less than unity, and unstable of this threshold is greater than unity.