Objective To analyze the diagnostic value of high frequency color ultrasound combined with CT for benign and malignant thyroid nodules in hashimoto's thyroiditis. Methods 74 cases of hashimoto's thyroiditis with thyroid nodules admitted to our hospital from November, 2016 to April, 2018 were selected as study objects. All the patients underwent high-frequency color ultrasound and CT examination, and the main image features of benign and malignant thyroid nodules in high-frequency ultrasound and CT were summarized.The specificity, sensitivity and detection rate of benign and malignant thyroid nodules were calculated by using the surgical or pathological results as a reference. Results The echo of thyroid parenchyma of 69 benign thyroid nodules mainly presented patchy low echo area, 21 nodules presented high echo, and 43 nodules had uniform echo distribution inside. The color doppler is characterized by a few blood flow signals. There was no significant change in the echo of thyroid parenchyma of 13 malignant thyroid micronodules, 7 of which presented a grid-like change, and 20 of which had a little blood supply. In the enhanced CT scan of benign thyroid micronodules, 31 nodules showed island enhancement, solid nodules were light and moderate enhancement, uneven enhancement ring existed at the edges, there was necrotic area in the malignant thyroid micronodules, and thyroid tissue infiltration and lymph node metastasis occurred in 4 patients. The specificity, sensitivity and detection rate of thyroid microscopic nodules diagnosed by high-frequency color ultrasound combined with CT were respectively 98.97%, 97.95% and 100%, significantly higher than the simple high-frequency color ultrasound and CT examination, and the difference had statistical significance (P＜0.05). Conclusion The diagnostic specificity, sensitivity and detection rate of benign and malignant thyroid nodules in hashimoto's thyroiditis by high-frequency color ultrasound combined with CT is high.