Objective: To investigate the clinical characteristics in pediatric patients with acute lymphoblastic leukemia (ALL) during induction period, analyze the risk factors of severe infections, in order to provide theoretical basis for clinical intervention. Methods: A retrospective analysis was conducted for the clinical data of 180 pediatric patients underwent CCCG-ALL-2020 protocol with newly-diagnosed ALL from June 2020 to June 2022 in Children"s Hospital of Nanjing Medical University. The distribution of infections, pathogenic bacteria and susceptible factors of severe infections were analyzed during induction period. Results: The incidence of infection among pediatric patients with ALL during induction period was 95.7% (180/188) with unknown infections being the most common (28.4%), followed by upper respiratory tract infections (23.6%) and lower respiratory tract infections (16.9%). Forty-eight (30%) of the patients developed severe infections, while 23.8% (43/180) experienced micro-biographically documented infections in which Gram-negative and Gram-positive bacteria were equally represented. The duration of hospitalization, hospitalization expenses and antibiotic cost per unit body surface area were significantly greater in severe infection group compared to the non-severe infection group (p <0.05). Medium-high risk (OR =2.804,95CI%: 1.234-6.375, p =0.014), ABL <35g/L (OR =4.708, 95CI%: 2.067-10.726, p<0.001) and duration of agranulocytosis >7 days (OR =3.697, 95CI%: 1.393-9.816, p =0.009) were ascertained as independent risk factors for severe infection during induction period. Conclusions: Infection was most frequently observed during induction period of ALL. Independent risk factors for severe infections included medium-high risk, ABL <35g/L and duration of agranulocytosis >7 days. It is imperative to implement appropriate preventive measures.