Introduction: This study aimed to evaluate procedural state anxiety and identify associated socio-demographic and clinical factors in Chinese pediatric leukemia patients. Methods: A convenience sample of 119 patients aged 8–18 years with acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML) undergoing bone marrow aspiration or lumbar puncture was recruited from a tertiary pediatric oncology center in China. State anxiety was assessed using the Chinese Version of the State Anxiety Scale for Children. Data were analyzed using R software (version 4.4.3). Non-normally distributed variables were presented as median (P25, P75). Group comparisons were performed according to the above socio-demographic and clinical variables using the Mann–Whitney U test for two-group comparisons and the Kruskal–Wallis test with Dunn’s post-hoc test for variables with more than two categories; P < 0.05 was considered significant. Results: The overall median CSAS-C score was 27 .0 (21.0, 32.0), indicating mild to moderate anxiety . Significant higher anxiety was associated with younger age, primary school education, AML diagnosis , and first-time procedures (P < 0.001). Conclusion: Procedural state anxiety is common among Chinese pediatric leukemia patients undergoing BMA or LP, with significantly higher levels observed in younger children, those with lower education levels, AML diagnosis and first-time procedures. These findings highlight the need to identify and focus on these high-risk groups in clinical practice.