Objective: To investigate the genetic pattern and mutation sites of a patient with Enlarged Vestibular Aqueduct (EVA). Methods: The venous blood of a patient clinically diagnosed with vestibular aquadtube dilatation and its healthy parents were collected, and the genetic sequence of the proband was detected by whole exon sequencing technology for bioinformatics analysis. The possible pathogenic genes and mutation sites of this child were identified, and the relevant mutation sites of the parents were further verified by Sanger sequencing method. Finally determine the pathogenic gene of the child; By means of single nucleotide polymorphism site analysis, amino acid conserved analysis and amino acid sequence analysis, the pathogenic mechanism of complex heterozygous mutations was analyzed, and the genetic pedigree of mutations was drawn. Results: The pathogenic mutation in this patient was located in SLC26A4 gene of 7q31, which was a complex heterozygous mutation consisting of c.919-2A>G, c.1746del G and c.563T>C. The c.919-2A>G mutation of SLC26A4 was inherited from his hearing father, while the c.1746del G and c.563T>C mutations of SLC26A4 were both inherited from his hearing mother. Conclusion: The three mutation sites of SLC26A4 gene carried by the proband were all clear recessive disease mutation sites associated with hearing impairment. Therefore, the above three mutations in SLC26A4 gene are presumed to cause disease in subjects in some form of complex heterozygosity.