Secondary outcomes include additional sleep parameters, pain scores, sedation scores, delirium scores, B-type natriuretic peptide (BNP) levels, cardiac troponin I (cTnI) levels, dosages of dexmedetomidine and sufentanil, cardiac intensive care unit (CICU) length of stay, total hospital length of stay, and parental satisfaction.<h4>Discussion</h4>This trial aims to provide high-quality evidence on maternal voice to improve postoperative sleep quality in children with CHD.<h4>Trial registration numbers</h4>Chinese Clinical Trial Registry (https://www.chictr.org.cn) ChiCTR2500111004. This evidence concerns the gene NPPB and delirium.