Background: To understand the characteristics and outcomes of acute heart failure (AHF) in children with solid tumors during the treatment process, share treatment experiences, and provide management strategies for monitoring, treatment, and prevention. Methods: Five representative cases of children with solid tumors were selected to summarize the clinical features and treatment effects during the occurrence of AHF. The possible triggers and time points for the onset of AHF were analyzed, along with treatment responses and influencing factors. Results: All five cases of children with solid tumors exhibited symptoms of AHF after chemotherapy, with heart functions staging from class II to class IV. Most cases occurred during the bone marrow suppression period with a noticeable increase in heart rate. All children received oral anti-heart failure treatment and nutritional myocardial therapy. Two children with heart function class II returned to normal after oral medication; three children with heart function class IV received intravenous vasoactive agents followed by regular reinforcement in the later stage. The heart function improved in all three cases (heart function class IV), with one case returning to normal, one case with slow recovery in noncompaction cardiomyopathy gradually approaching normalcy, and one case with only mild improvement in heart function despite concurrent renal dysfunction. Conclusions: Children with solid tumors are susceptible to AHF during the bone marrow suppression period, and an increased heart rate serves as an early warning signal. Active anti-heart failure treatment is effective. Renal dysfunction emerging as a significant factor influencing poor recovery of heart function.