Objective To analyse vitamin D, Procalcitionin（PCT）, C-reactive protein（CRP） level of Premature rupture of membranes neonatal cord blood and relation of neonatal early-onset sepsis. Methods A total of 105 cases of parturients admitted to the Baiyun Branch of Nanfang Hospital of Southern Medical University from May 2019 to October 2020 were retrospectively selected as the observation objects, according to whether maternal premature rupture of membranes occurred was divided into premature rupture group (n=45) and control group (n=60). The differences of neonatal umbilical cord blood vitamin D, PCT, CRP levels between premature rupture group and control group were compared, the differences of neonatal umbilical cord blood vitamin D, PCT, CRP levels in premature rupture group between neonatals with and without early-onset sepsis were compared, the correlation of umbilical cord vitamin D,PCT, CRP levels between premature fetal membrane rupture and early-onset sepsis were analyzed. Results The level of vitamin D in premature rupture group was lower than control group, the levels of PCT, CRP in premature rupture group were higher control group, and the differences were statistically significant (P<0.05). The cord blood vitamin D level of neonates with early onset sepsis in the premature rupture group was lower than that of the neonates without early onset sepsis in the premature rupture group，and cord blood PCT, CRP of neonates with early onset sepsis in premature rupture group were higher than those of neonates without early onset sepsis in premature rupture group, and the differences were statistically significant (P<0.05). Correlation analysis showed that neonatal umbilical cord blood vitamin D level was negatively correlated with early onset sepsis, PCT, CRP was positively correlated with early onset sepsis (P＜0.05). Conclusion Low neonatal cord blood vitamin D in neonatals with increased PCT, CRP level is related to early-onset sepsis after childbirth. Prevent low vitamin D level during pregnancy. Monitoring PCT, CRP level can reduce the probability of premature hairstyle sepsis, which has positive significance to neonatal prognosis.