Abstract:Objective To investigate the clinical significance of liquid based cytology and conventional smear in ultrasound-guided fine needle aspiration(US-FNA) in the diagnosis of thyroid nodules. Methods A total of 70 patients with thyroid nodules from July 2017 to October 2019 were selected as the subjects,and postoperative histopathological diagnosis was taken as gold standard.The consistency of pathological results of liquid based cytology,conventional smear and combined detection with surgical histopathological diagnosis was analyzed.At the same time,the positive rates and false positive rates of the three methods were compared. Results According to the results of postoperative histopathology as the gold standard,the diagnostic efficacy of various methods in the diagnosis of malignant thyroid nodules was analyzed.(1)The results of liquid-based cytology were consistent with those of traditional cell smears,but the consistency was poor (κ=0.205,P>0.05).(2) The results of liquid-based cytology,traditional cell smear and the combination of the two methods were consistent with the results of postoperative histopathology,respectively（κ=0.744，0.826，0.882，all P<0.01）,and the consistency between the combined method and postoperative histopathology was higher than that of single liquid-based cytology and traditional cell smear.(3) The diagnostic accuracy of combined method (97.56%)>single traditional cell smear (90.24%)>single liquid-based cytology (80.49%);the false positive rates of combined method,single traditional cell smear and single liquid-based cytology were 6.90%,6.90% and 3.45%,respectively. Conclusion US-FNA liquid based cytology combined with conventional smear can effectively improve the consistency between single detection and histopathological identification of malignant thyroid nodules,and effectively improve the accuracy of diagnosis.