Objective To analyze the expression of Yes-associated protein and risk factors in differentiated thyroid carcinoma. Methods Clinical data of 152 patients with differentiated thyroid carcinoma and 27 cases of benign thyroid tumor from Changji Hui Autonomous Prefecture People’s Hospital of Xinjiang, were analyzed retrospectively. According to the expression levels of Yes-associated protein in differentiated thyroid cancer and benign thyroid tumor, univariate Chi-square test and multivariate Logistic regression methods were used to analyze the relationship between Yes-associated protein and gender, age, thyroid stimulating hormone(TSH) level, nodule size, capsule integrity, histological type and lymph node metastasis, in order to find out risk factors in differentiated thyroid cancer. Results The positive rate of expressed Yes-associated protein in benign thyroid tumor group was 66.7%(18/27), which was significantly higher than 31.58%(48/152) of differentiated thyroid cancer group, and the difference was statistically significant(χ2=12.127, P<0.01). Under an optical microscope, changes of Yes-associated protein were found to be mainly located in the nucleus and cytoplasm , and in benign thyriod tumor the degree of staining was deep, strong positive or moderately positive; differentiated thyroid carcinoma was lightly stained or no staining, weakly positive or negative. Chi-square test showed that the expression of Yes-associated protein was not affected by sex, age and pathological type(χ2= 0.419, 0.221, 0.315, all P >0.05); TSH level, nodule size, capsule integrity, lymph node metastasis had an impact on the expression of Yes-associated protein which was down regulated (χ2=4.020, 8.424, 4.386, 6.673, P<0.05 or<0.01). Logistic regression analysis showed that the nodule size was not a risk factor ( odds ratio , OR ) of Yes-associated protein expression (OR=1.929, P>0.05); TSH levels above 4.5 mU/L, lymph node metastasis and envelope incomplete were risk factors that down regulated the expression of Yes-associated protein (OR=2.167, 2.665, 3.048, all P<0.05). Conclusion Yes-associated protein is down regulated in differentiated thyroid cancer. Elevated TSH levels , incomplete capsule and lymph node metastasis are risk factors of Yes-associated protein down expression and differentiated thyroid cancer.