ABSTRACT: Objective The incidence of acute kidney injury (AKI) in pediatric patients has been increasing over the years, and AKI significantly impacts children’s health and quality of life. This article reviews the current epidemiological research on pediatric AKI. Methods The clinical data of hospitalized children aged 0 to 14 years from 20 different hospitals in Hunan Province, China, collected from December 2017 to February 2018, were analyzed. The incidence rate, misdiagnosis rate, main causes, and medical costs of AKI in hospitalized children were examined. Results A total of 29,639 patients were included, with an AKI incidence rate of 4.34% (1286/29,639). Among the 1286 AKI patients, 863 (67.11%) were classified as AKI stage 1324 (25.19%) as AKI stage 2, and 99 (7.7%) as AKI stage 3. AKI patients had significantly longer hospital stays [6.0 (4.0, 10) days vs. 6.0 (4.0, 8.0) days, p < 0.001] and higher hospitalization costs [3375.22 (1600, 6083.83) yuan vs. 2729.4 (1659.45, 8216.65) yuan, p = 0.003] than non-AKI patients. The mortality rate (1.2% vs. 0.1%, p < 0.001), intensive care unit (ICU) transfer rate (8.7% vs. 5.97%, p < 0.001), and use of invasive mechanical ventilation (3.6% vs. 1%, p < 0.001) were significantly greater in patients with AKI than in those without AKI patients. The etiology of AKI varied among different age groups, and dehydration, diarrhea, and shock were the main causes of pre-renal AKI. Conclusion The incidence and missed diagnosis rates of AKI in hospitalized children were high. AKI prolongs hospital stays, increases hospitalization costs, and increases the risk of mortality in children.