Objective To analyze the diagnosis, treatment and prognosis of group B streptococcus (GBS) septicemia or combined with meningitis in newborns whose mothers were with negative GBS screening during pregnant period. Methods Clinical data of 10 cases of maternal negative GBS screening but neonatal GBS septicemia or combined with meningitis in department of neonatology from June 2014 to October 2016 were retrospectively analyzed. Results Of the 10 newborns, 7 had early onset and 3 had late onset. Neonatal procalcitonin increased in all cases, including 7 cases of septicemia or combined with meningitis, brain MRI showed 2 cases were with meningeal enhancement, and 1 case had decreased white matter density. One case was treated with amoxicillin/sulbactam alone, others were treated with combination of drugs. One case died 24 hours after birth, others were followed up for 24 months, 2 cases were underdeveloped and the other 7 cases were normal. Ten strains of GBS were sensitive to ampicillin, vancomycin, furantoin, tigecycline and penicillin, but resistant to clindamycin and tetracycline, levofloxacin-and ciprofloxacin-resistant isolates were both 3 strains. Conclusion Prenatal screening during pregnancy is still likely to be missed, neonatal GBS septicemia or combined with meningitis is serious and progresses rapidly, it is necessary to detect and give targeted anti-infective treatment, give combined anti-infective treatment if necessary.