Objective　To explore the clinical phenotype and gene abnormality of Coffin-Siris syndrome. Method　The clinical data of Coffin-Siris syndrome in a child diagnosed by high-throughput sequencing technology were retrospectively analyzed, and the related literature was reviewed. Results　A male child had feeding difficulties, growth retardation and special facial features after birth. Gene detection showed a mutation of c.6683C>A (p.Ser2228*) in ARID1B gene, , which was a de novo mutation and predicted to be pathogenic. Conclusion　Coffin-Siris syndrome is a rare genetic disease and is difficult to diagnose in early stage, and genetic testing helps the diagnosis.