Abstract: The characteristics of air flowing through a cigarette were investigated, and the analytical solution to the pressure drop and velocity distribution inside cigarette was obtained following the establishment of an one-dimensional (1-D) mathematical analytical model under different puff profiles. It indicated that the pressure drop was in compliance with sectional linear function, and the air velocity variation was compliant to a quadratic function in tobacco section of cigarette and as step function in filter section; the total ventilation rate and filter ventilation rate of cigarette remained unchanged independent of puff profiles. The established mathematical model is helpful for understanding the air flowing characteristics inside an unlit cigarette.