The room-temperature switching effect is of great interest for many applications, such as smart buildings, sensors, thermal energy storage and automatic temperature control. In this paper, we report a room-temperature switchable carbon nanotube (CNT)/hexadecane composites. Electrical conductivity, thermal conductivity and permittivity of the CNT/hexadecane composites can be regulated around 18°C and the maximal switching ratio reaches 5 orders of magnitude, 3 times and 106.4, respectively. The switching behavior of composites is caused by rearrangement of the carbon nanotube fillers in hexadecane matrix during liquid-solid phase transition. It is found that surface modification is necessary to improve dispersion stability. Effects of filler properties on switching behaviour are also discussed.