Objective To further strengthen the understanding of the genesis of thyroid tumors through the analysis of thyroid nodules in the clonal origin. Method The related literatures which discussed the clonality of thyroid nodules were reviewed and analyzed. Results About the clonal origin of thyroid nodules， the X chromosome inactivation detection and single gene mutation detection were the most widely chosen one at present. Most of the materials available at present related to X chromosome inactivation proposed that major part of the thyroid nodules were monoclonal and the malignant cells spreaded by means of the inner lymphatic vessel net，whereas polyclonal and monoclonal thyroid nodules coexisted occasionally. Only BRAF mutation was found of certain importance in clonal origin identification in the thyroid nodules. Conclusions Thyroid nodule is prevalent in clinical practice，while the clonality of thyroid nodules especially the thyroid tumor is not clear. And for the time being the commonly used methods to identify the clonal origin of thyroid nodule are X chromosome inactivation and single gene mutation detection. Published results confirm the finding of X chromosome inactivation methods that the majority of thyroid nodules are monoclonally originated.