In our paper, we analyze the endemic influenza in Thailand by using the real data between 1997 and 2013. The numerical simulations for two mathematical models have different behaviors. Fig. 5 shows time series solution when there is no the effect of incubation period and re-infection in human population. Fig. 6 shows time series solutions when there is the effect of incubation period and re-infection. The values of parameters are satisfied Routh-Hurwitz criterions for the endemic equilibrium states. Moreover, we consider the basic reproductive number in each model. For the first model which no effect of incubation period