Abstract: Objective: To Analysis the clinical significance of frozen section for the diagnosis of thyroid neoplasms and discuss the cause of wrong diagnosis. Methods: The diagnostic reports of intraoperative frozen sections and paraffin sections were analyzed retrospectively in 776 cases with thyroid neoplasms since Oct 1995 to Jul 2003. Results: The original diagnosis of frozen section was accurate in 758 of 776 cases (97.7%) wrong diagnosis in 15 of 776 (1.9%). False of negative in thyroid carcinoma is 14 of 131(10.7%). Conclusions: Frozen section is valuable in the diagnosis of thyroid neoplasms and is important for the choice of operation method. The factors affecting the caccuracy of frozen section diagnosis includes the qulity of the section, the diversity of the disease and the limition of the section material.