Objective　To explore the clinical and cytogenetic characteristics of 8p inverted duplication deletion [inv dup del (8p)] syndrome. Method　The clinical data and cytomolecular genetic analysis data of a child with inv dup del (8p) syndrome were retrospectively analyzed. Results　A 6-month-old girl had clinical manifestations of developmental delay, special facial features, congenital heart disease, and laryngomalacia. Chromosome karyotype analysis of peripheral blood lymphocytes showed that the child was 46, XX, der (8) inv dup (8) (p21), del (8) (p23), and there was no abnormality in her parents. Copy number analysis (CNV) of high-throughput sequencing genome was used to accurately locate the chromosomal regions with abnormal copy number changes. The CNV detection showed the deletion of 6.96 Mb in 8p23.3-p23.1 (160001-7120000) region and the duplication of 15.38 MB in 8p23.1-p21.1 (12560001-27940000) region. Real-time PCR verification of CNV showed a 5.4 Mb normal copy number fragment between the duplicate and deleted fragments. Based on the combination of clinical manifestations and various test results, the child was diagnosed with inv dup del (8p) syndrome. Conclusion　Clinical features, karyotype analysis of peripheral blood, CNV and fluorescent quantitative PCR technology in combination can effectively diagnose inv dup del (8p) syndrome.