How long a 31-week preterm baby needs to stay in an incubator is determined by the baby’s specific medical condition. The incubator is designed to keep both the body temperature and humidity of the preterm baby within a stable temperature and humidity range. Insulation box humidity is generally based on the weight of the child and the age of birth, maintained at a moderate temperature, the moderate temperature of preterm babies is generally 32 ~ 35 ℃, the general relative humidity of the box at 55% ~ 65%, to help stabilize the body temperature of preterm babies. Preterm babies in the room temperature of 22 ~ 24 ℃, weight more than 2000 grams, body temperature remains within the normal range, the general condition is good, the ability to suck food, can be sent out of the incubator, if the weight is less than 2000 grams, in the incubator to stay for more than a month, if the physical condition is good, the doctor will be based on the recovery of preterm babies, to determine whether it can be out of the incubator. The daily care of premature babies should pay attention to maintaining appropriate room temperature and indoor humidity, reducing adverse stimuli, dimming indoor light. Prevent infections, breastfeed as much as possible, and improve the immunity of premature babies to enhance their health.