Objective:The aim of the study was to investigate the diagnostic value of fine needle aspiration cytology (FNAC) and its clinical application.Methods:From April 2009 to February 2011,thyroid FNAC were performed in a total of 186 patients with thyroid nodule or mass in our hospital and 78 of those 186 patients subsequently underwent thyroidectomy.The FNAC findings were compared with the results of the corresponding histological diagnosis.Results:The results of thyroid FNAC for 186 patients showed that,(1) 166 cases of benign lesions,the detection rate was 89.24% (166/186),including 96 cases of nodular colloid goiter (51.61%),28 cases of simple colloid goiter (15.05%),38 cases of Hashimoto’s thyroiditis (HT) (20.43%) and 4 cases of thyroid adenoma (2.15%);(2) 4 cases of suspicious malignant lesion,the detection rate was 2.15% (4/186);(3) 16 cases of malignant tumor,the detection rate was 8.60% (16/186).Seventy eight patients including malignant (16),suspicious malignant (4),HT (20) and nodular colloid goiters (38) cases diagnosed by FNAC were performed operation with thyroidectomy and the postoperative histopathologic results showed that there were 2 cases HT combined thyroid papillary carcinoma in HT 20 cases by FNAC,15 cases of thyroid papillary carcinoma and 1 case of follicular carcinoma in 16 cases of malignant tumor by FNAC and 4 case of thyroid papillary carcinoma in 4 cases of suspicious malignant by FNAC.Conclusion:Thyroid FNAC is a valuable and reliable method for the diagnosis of the thyroid nodules or mass or even most diffuse thyroid diseases.Diagnosis of HT and thyroid papillary carcinoma can be made by thyroid FNAC.There was larger hint value for nodular colloid goiter and simple colloid goiter according to thyroid FNAC. Objective: The aim of the study was to investigate the diagnostic value of fine needle aspiration cytology (FNAC) and its clinical application. Methods: From April 2009 to February 2011, thyroid FNAC were performed in a total of 186 patients with thyroid nodule or mass in our hospital and 78 of those 186 patients who underwent thyroidectomy. The FNAC findings were compared with the results of the corresponding histological diagnosis. Results: The results of The thyroid FNAC for 186 patients showed showed, (1) 166 cases of benign lesions, the The detection rate was 89.24% (166/186), including 96 cases of nodular colloid goiter (51.61%), 28 cases of simple colloid goiter (15.05%), 38 cases of Hashimoto’s thyroiditis (HT) (20.43%) and 4 cases of thyroid adenoma (2.15%); (2) 4 cases of suspicious malignant lesion, the detection rate was 2.15% (4/186); (3) 16 cases of malignant tumor, the detection rate was 8.60% (16/186). Seventy eight patients including malignant (16), suspicious malignant (4), HT (20) and n odular colloid goiters (38) cases diagnosed by FNAC were performed with thyroidectomy and the postoperative histopathologic results showed that there were 2 cases of HT combined thyroid papillary carcinoma in HT 20 cases by FNAC, 15 cases of thyroid papillary carcinoma and 1 case of follicular carcinoma in 16 cases of malignant tumor by FNAC and 4 cases of thyroid papillary carcinoma in 4 cases of suspicious malignant by FNAC. Confc: Thyroid FNAC is a valuable and reliable method for the diagnosis of the thyroid nodules or mass and even most diffuse thyroid diseases. Diagnosis of HT and thyroid papillary carcinoma can be made by thyroid FNAC. There was larger hint value for nodular colloid goiter and simple colloid goiter according to thyroid FNAC.