Objective: To explore the value of ultrasound guided fine needle aspiration biopsy (US-FNAB) cytology in the qualitative diagnosis of thyroid nodules. Methods: A total of 66 patients with thyroid nodules admitted to the hospital were enrolled between January 2022 and March 2024. The results of postoperative pathological examination or clinical follow-up were selected as the golden standard. All patients underwent routine ultrasound and US-FNAB examinations. The cytological classifications consistency of malignant thyroid nodules between US-FNAB and pathological examination was analyzed by Kappa test. Results: In the 66 patients with thyroid nodules, pathological examination showed that there were 29 malignant cases and 37 benign cases. In Bethesda cytological classifications, there were 8 cases, 15 cases, 7 cases, 4 cases, 14 cases and 18 cases with types I-VI, respectively. Routine ultrasound showed that there were 33 cases with malignant thyroid nodules, including 23 confirmed cases, 10 cases with misdiagnosis and 6 cases with missed diagnosis. US-FNAB showed that there were 32 cases with malignant thyroid nodules, including 28 confirmed cases, 4 cases with misdiagnosis and 1 case with missed diagnosis. Kappa consistency between routine ultrasound, US-FNAB and pathological examination for detecting nodule nature was 0.515 and 0.848, respectively. There were differences in sensitivity, accuracy rate and negative predictive value between routine ultrasound and US-FNAB (P<0.05). Conclusion: The detection efficiency of US-FNAB is high in patients with thyroid nodules, and its qualitative diagnosis is more accurate.