Abstract: Objective: To investigate the relationship between laminin and invasion,lymph node metastasis in thyroid papillary carcinoma.Methods: Laminin was detected by immounohistochemistry S-P method in 20 thyroid adenoma cases and 64 thyroid papillary carcinoma cases.Results: The positive rate of laminin in the thyroid papillary carcinoma patients was 82.8% and 40.0% in adenoma patients,the difference was significant (P<0.01).The rates of lymph node metastasis were 16.7%,58.1%and 90.0% respectively in the laminin expression of grade from Ⅰ to Ⅲ,the difference was significant (P<0.005).The rate of laminin expression in cytoplasm was 21.2% in patients with lymph node metastasis,but 3.2% in patients without lymph node metastasis.The difference was not significant(P>0.05).Conclusions: In the thyroid papillary carcinoma,the expression of laminin is related to benign,malignant and metastasic tumors.The phenomena of dispersion,penetration and cytoplasmic expression are found in the neoplastic cells invading brim and metastasic lymph node.