Abstract: Objective: To investigate the expressions of p53 and p16 in the papillary thyroid carcinoma(PTC) and their clinical significance.Methods: Immunohistochemistry was used to detect the expressions of p53 and p16 in 157 cases of PTC and 30 cases of thyroid tumor.Results: The expression of p53 in PTC was significantly higher than that in benign tumors(P<0.005),and with the increase of the pathological grade of PTC,the expression of p53 increased significantly(P<0.01),the expression of p53 in cases with neck lymph node metastasis was higher than that in cases without(P<0.05),the expression of p16 in PTC was significantly lower than that in benign tumors(P<0.005),and with the increase of the pathological grade of PTC,the expression of p16 was reduced significantly(P<0.01),the expression of p16 in cases with neck lymph node metastasis was significantly different compared with that of cases without(P<0.01).Conclusions: The mutation of gene p53 and the loss expression of gene p16 may promote the genesis,progress and metastasis of PTC;gene p16 may play an important role in the middle and advanced stages of PTC,which is of great clinical value and can be used as a reference index in judging the malignant degree of PTC.