Objective　To explore the genetic mutation in Kabuki syndrome and the correlation between genotype and phenotype. Methods　The clinical data of Kabuki syndrome in one proband were collected, and the suspected Kabuki syndrome was diagnosed by high-throughput gene sequencing, biological information analysis, database screening and other methods. Results　A 10-year-old boy had slow response since birth, recurrent otitis media, and special facial features (long palpebral fissure extending laterally, eversion of the lateral third of the lower eyelid, arched eyebrows with lateral 1/3 sparse eyebrows, flat nasal tip, short septum of nose, large and prominent ears, abnormal eruption and arrangement of teeth, and micrognathia). The child had abnormal renal function with progressive aggravation. Genetic analysis confirmed that there was a heterozygous variation of c.8214dupC (p.Phe2739fs) in the KMT2D gene of the child, which has not been reported in the literature. No variation was found in this locus in the parents, and it was a new mutation. According to the American College of Medical Genetics and Genomics (ACMG) guidelines, the comprehensive analysis of this variation revealed that it is consistent with "pathogenic". Conclusions　High throughput sequencing and bioinformatics analysis are helpful for the diagnosis of Kabuki syndrome. A new mutation in KMT2D gene was found, which had not been reported before.