Features: 1. With physiological features of preterm infant: Under 2500 grams in weight, less than 47cm in body length, soft skin with bright red, thin epidermis and visible of blood vessel, loose and wrinkling facial skin, flabby cervical muscle, hypotonia of limbs, hypertrichosislanuginose, soft ear conch, unclear areola mammae, little dermatoglyphic patterns of sole, retained testicle of male infant, and labium majus can not cover labium minus for female; Can observe the physiologic icterus. 2. Bregmatic Palpation for preterm infant, broad seam of bones of cranium, large fontanel and soft fringe of fontanel; 3. Cleaning and bathing exercise of preterm infant in the incubator; 4. Sputum suction and nasal feeding practice.