Abstract: To study the temperature distribution and the puff-by-puff release behaviors of key smoke components of an electrically heated cigarette (iQOS), temperature distributions in the tobacco section and the residual contents of the key components were determined under two different smoking profiles. The volume averaged temperatures and the three-dimensional temperature fields in the heated tobacco section were determined. The results showed that: 1) By comparing a square-puffing profile and a bell-puffing profile, the maximum temperature difference between different positions of the tobacco section was less than 10 ℃, and the maximum relative deviations among the residual contents of the key smoke components were less than 5%. 2) By comparing different puffing volumes (35-55 mL), the maximum temperature difference between different positions of the tobacco section was less than 20 ℃, and the averaged relative deviations of the residual contents for the key smoke components were less than 10%. 3) The volume averaged temperature in the tobacco section of the electrically heated cigarette gradually increased with the puff number and displayed in a zigzag pattern during puffing.