To keep a constant core body temperature is important not only for comfort but also for health. The maintenance of normothermia during operation will reduce the incidence of numerous complications, including morbid cardiac events, surgical-wound infection, and coagulopathy. Many devices of noninvasive internal rewarming were developed to elevate the warming rate. To investigate the warming effectiveness of electric heating pad on different part of body surface, three sites with different subcutaneous fat thickness were compared. Both skin temperature of 22 points around whole body and verbal analog score were collected before and after heating. The fat thickness of three tested sites was measured by skinfold technique. The pilot results revealed that the thicker is the fat thickness, the worse is the warming effectiveness.