Introduction: Preschool children, undergoing rapid neurocognitive development, are particularly susceptible to cognitive late effects from cancer and its treatments. While computerized cognitive training shows promise in addressing these issues, its feasibility for preschool cancer patients remains largely unexplored. Objective: The aim of this study was to determine whether Cognifit, a gamified computerized cognitive training intervention, is efficacious in improving the cognitive function of preschool children with cancer. Results: Ultimately , 91 children (89.2%) completed the study and were included in the analysis. At the endpoint of the study compared with the control group, children in the computerized cognitive training condition exhibited a greater improvement in executive function (β= -18.693, 95% CI -2.627 to -0.943; P < 0.001), After the intervention, greater improvements were observed in the training group in terms of attentional stability (β= 0.302, 95% CI 0.178 to 0.977; P = 0.008) and quality of life (β= 22.23, 95% CI0.66 to 3.08; P < 0.001). Furthermore, after the intervention, the satisfaction score of the experimental group was significantly higher than that of the control group (3.95 ± 0.65 vs. 2.00 ± 0.46, P < 0.001). Conclusions: The research results indicate that computerized cognitive training is feasible and effective for preschool cancer patients, which can enhance their executive function, attention stability , and quality of life, and the satisfaction rate is also high. However, it is necessary to conduct larger-scale multi-center effectiveness trials and longer follow-up periods to confirm these findings and evaluate the persistence of the therapeutic effects.