Objective: To explore the significance of liquid-based cytology test (LCT) for the diagnosis of thyroid micronodular lesions. Methods: LCT with ultrasound-guided fine needle aspiration was performed on 119 patients with thyroid micronodular lesions; the LCT results were summarized and compared with the postoperative histopathological results to probe into the liquid-based pathological characteristics and the diagnostic efficacy of LCT. Results: LCT results on the 119 patients with thyroid micronodular lesions: specimens cannot be diagnosed in 11 (9.24%) patients; benign in 41 (34.45%) patients; atypia of undetermined significance in 10 (8.4%) patients; follicular neoplasm or suspicious for a follicular neoplasm in 4 (3.36%) patients; suspicious for malignancy in 29 (24.37%) patients; and malignancy in 24 (20.17%) patients. Among the 119 patients with thyroid micronodular lesions, 59 received surgical treatment and obtained histological diagnostic results, using which as the gold standard the diagnostic sensitivity of LCT was calculated at 95.74%, the specificity at 63.64%, the positive predictive value at 92.84%, and the negative predictive value at 77.78%. Conclusion: Given the difficulties in both imaging and pathological diagnosis of thyroid micronodular lesions, LCT could significantly improve the diagnostic accuracy, allowing accurate preoperative diagnosis of most of the lesions, which supports its extensive clinical application.