Objective By analyzing the clinical features, laboratory tests, pathogenic bacteria culture and the treatments of infants and toddlers with urinary tract infection UTI accompanied with sepsis, we aim to guide the further clinical treatments and prevention. Methods We selected 83 cases from January 1, 2014 to December 31, 2016 in our hospital as the research objects which were accepted the diagnosis and treatments of urinary tract infection complicated with sepsis. Its clinical manifestations, laboratory tests, bacteriology examination and treatment prognosis were retrospectively analyzed. Results Among the selected infants and toddlers diagnosed with urinary tract infection complicated with sepsis, male patients were more common. Symptoms of systemic poisoning were observed in the majority especially in the children aging under 6 months, with severe sepsis and septic shock as the first manifestation, while conventional symptoms were not obvious. Biological markers of bacterial infection were significantly changed. In bacterial culture, 22 strains of bacteria were detected, Escherichia coli accounted for 54.55% (12/22), were almost sensitive to cefepime, and all sensitive to imipenem and meropenem; Enterococcus following accounted for 22.73% (5/22), could be more sensitive to vancomycin, linezolid, teicoplanin. Conclusion Urinary tract infection is common in under 3 years old babies. Patients aging under 6 months are more likely to be complicated with severe sepsis and septic shock. Therefore, we should be especially vigilant of the UTI among the babies whose first manifestations appear to be sepsis only. It is important to find out the site of infection as early as possible, in order to prevent misdiagnosis. It is also critical to use broad-spectrum antimicrobial therapy within 1 hour when severe sepsis is diagnosed in order to reduce the mortality of sepsis in infants and improve the prognosis.