Abstract: 　Objective　To explore the characteristics of TTN gene mutation in familial dilated cardiomyopathy. Method The blood samples were collected from a 6-year-old boy with  confirmed familial dilated cardiomyopathy and his mother who had familial dilated cardiomyopathy with familial dilated cardiomyopathy, as well as his father, grandparents and his maternal grandmothers without who didn’t have familial dilated cardiomyopathy history, and genomic DNA was extracted. Nextgeneration DNA sequencing (NGS) was used to detect 213 cardiovascular disease-related genes in the child, and the suspicious sites were identified by bioinformatics analysis and then verified by Sanger sequencing. Results　Three missense mutations of TTN gene on chromosome 2, c.53498A>T (p.Tyr17833Phe), c.66590G>A (p.Arg22197Gln) and c.8434G>C (p.Val2812Leu), were carried by the child. Each of the above mutation could affect the functional expression of the protein. Conclusion　This is the first time to find three variants of c.53498A>T, c.66590G>A and c.8434G>C in TTN gene.