Abstract: Objective To explore the relationship between genetic factors and the development of Tourette syndrome.Methods A genetic epidemiologic case-control study including 200 pedi-grees(100 cases and controls) was carried out to estimate the segregation ratio and the heritability of Tour ette syndrome by using the method of Li-Mantel-Gart and Falconer respectively and to assay by conditional logistic reg ression analysis.Results The results showed that the segregation ratio of Tourette syndrome was 0.1212,significantly less than 0.25 and the genetic model belonged to polygenetics.The heritability of the first-degree relatives was 45.66%.Simple and multiple condition logistic regression analysis also showed that genetic factor was one of the most important factors in the development of Tourette syndrome.Conclusion Genetic factor was an important factor in the occurrence of Tourette syndrome.The genetic model belonged to polygenetics.