Purpose To evaluate the diagnostic value of Chinese thyroid imaging reporting and data system(C-TIRADS)and American thyroid association(ATA)guidelines in papillary thyroid carcinoma(PTC).Materials and Methods A total of 259 patients(339 nodules)with definite pathological results after thyroid nodule surgery in the 909th Hospital of the Joint Logistic Support Force(the Affiliated Southeast Hospital of Xiamen University)from July 2019 to May 2021 were divided into benign thyroid nodule group(150 cases,210 nodules)and PTC group(109 cases,129 nodules).General data and nodule ultrasonographic characteristics of the two groups were retrospectively analyzed.Nodules were classified by the two guidelines,and were compared with surgical pathological results,the receiver operating characteristic curve was drawn to evaluate the diagnostic value of the two guidelines for PTC.Results There were statistically significant differences between the two groups in the malignant ultrasonographic features of"solid,blurred/irregular edges or extrathyroid invasion,verticality,low or very low echo,microcalcification"(χ2=123.67,132.71,103.82,4.58,137.93,all P<0.05),and most commonly seen in the PTC group.Unlike C-TIRADS,61 nodules were not clearly classified in the ATA guidelines,accounting for 17.99%(61/339).The areas under the curves of C-TIRADS and ATA guidelines were 0.952(0.924-0.972)and 0.942(0.911-0.964),with no statistically significant differences(Z=0.943,P=0.346).The optimal cutoff values of the two groups were 4b and highly suspicious malignancy,and the sensitivity,specificity and accuracy were 0.930(120/129)vs.0.822(106/129),0.857(180/210)vs.0.943(198/210),0.885(300/339)vs.0.897(300/339),respectively.There were significant differences in sensitivity and specificity(χ2=6.99,8.57,both P<0.01),C-TIRADS had the highest sensitivity,ATA guidelines had the highest specificity,but there was no significant difference in accuracy(χ2=0.24,P=0.622).Conclusion Both C-TIRADS and ATA guidelines may be highly effective in the diagnosis of PTC,but C-TIRADS can be applied to the ultrasonographic manifestations of all thyroid nodules,and is less affected by the clinical experience of sonographers,so it is easier to be promoted in clinical practice.