 The current study adopts randomized, double blind, controlled intervention trial, gives Oropharyngeal administration of colostrums to very low birth weight infants in intervention group and Oropharyngeal administration of Normal saline to control group. All indicators in this study are discrete traits, for sIgALactoferrin number in Saliva and urine, number of CRP,time Begin oral feeding,time up to full enteral feeding, Persons chi-square tests were used for comparisons. For Blood culture results,The number of necrotizing enterocolitis NEC occurred, the investigators use Chi-square tests for comparisons between two groups. The study expects that Oropharyngeal administration of colostrum to very low birth weight infants can increase the secretion of sIgA in urine and saliva. 