Objective　To investigate the copy number variants of a developmental delay patient by applying single nucleotide polymorphisms array technique and to analyze the relationship between the clinical manifestation and copy number variants. Methods　Single nucleotide polymorphisms array was used to detect genomic copy number variants in a child with development delay and her phenotypic normal parents. Results　The patient had a 7. 9-Mb deletion at 8p23.3-p23.1 and a 27.4-Mb duplication at 8p23.1-p11.23, which were confirmed as pathogenic copy number variants after comparative analysis with database. Conclusions　Single nucleotide polymorphisms array could serve as a useful method to diagnose developmental delay patients and analyze pathogenesis.