Sleep is recognized as a phenomenon controlled by the circadian rhythms. It is generally believed that sleep is important for stabilizing the energy, supporting healthy immune system of human body, besides, it is beneficial for brain plasticity and mental health [1,2]. The thermal environment while sleeping are perceived by human beings both cutaneously stimulated and emotionally provoked. A preferable thermal environment should be within the thermal regulation range of human body and evoke the best thermal sensation. With regard to the thermal environment for sleeping during night, some researchers [3-5] have performed experiments to define the optimal indoor temperature in order to reach the thermal comfort condition. However, the recommended temperature were in a large range, and the role of bed cover or quilt was underestimated. People sleep with bedcovers for most of the time. The use of bedcover allowed for the development of an isolated high bed climate temperature, which was critical for maintaining both a high level of skin blood flow and skin temperature during sleep [6]. As a result, the thermal environment which human body exposed to turned out to be the microclimate in the bed, ambient conditions exerted only indirect influence on the covered body. Moreover, the quilt coverage was not the whole body in general, that is, people would leave head outside the covers. In this case, people experienced different thermal environment for different parts of the body at the same time. How does these two thermal environments affect the thermal sensation respectively? What is the thermal comfort environment for both the body parts?