Owing to the more obvious quantum tunneling effect, Carbon Nanotube Field Effect Transistors (CNFETs) take on different scaling property from that of silicon based Metal-Oxide-Semiconductor (MOS) transistors. The scaling properties of Conventional MOS-like Carbon Nanotube Field Effect Transistors (C-CNFETs), on the other hand, differ from those of Tunneling Carbon Nanotube Field Effect Transistors (T-CNFETs) due to different operating mechanism. As a result, study on the scaling property is one of the most important means of searching for the application potential of the device. The band-to-band tunneling, however, has not been taken into account in previous researches. A comparative study of the impact of band-to-band tunneling on the scaling property of C-CNFETs and T-CNFETs was carried out based on Non-Equilibrium Green's Function method. The research results reveal that these two kinds of CNFETs take on different or even opposite scaling properties. The research will offer a vigorous guidance for the device design to obtain a proper trade-off among area, speed and power in application.