Bloody stool and necrotizing enterocolitis(NEC) is two main focus in non-neonatal intensive care unit ward and usually lead to longed duration of hospitalization. Neutral temperature is a environmental temperature where the infant's body temperature is normal under resting state, and the changes of body temperature and skin temperature are less than 0.2-0.3 centigrade. According the definition, a suggested temperature range is set. For example, if an infant's body weight is more than 2500 gram, the initial set of environmental temperature is 31.3 centigrade with a range of 29.8-32.8 centigrade. low environmental temperature is a risk factor for Bloody stool and NEC. Therefore, how to set the optimal environmental temperature is a challenge.