Abstract Objective To evaluate the relationship between the mean moving distance (MMD) of thyroid nodule in FNA measured by M-mode ultrasound and its pathological result. Besides, evaluating the differentiating value of MMD in different pathological types. Methods: 145 cases of thyroid nodules diagnosed by pathology were collected, including 84 cases of malignant nodules and 61 cases of benign nodules. All the above patients underwent fine needle puncture of nodules under the guidance of ultrasound, and dynamic mapping was performed during the operation. All images were post-processed by Free-Xros M, and the puncture frequency and its displacement were measured. Support vector machine (SVM) was used to analyze the relationship between the average nodule displacement distance and its benign and malignant.Results: No statistically significant difference in size, shape, location, blood flow and FNA puncture frequency between benign and malignant thyroid nodules were found (all P >0.05). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of FNA were 85.96%, 85.57%, 79.03%, 90.24%, 85.51% and 0.855 respectively. Conclusion: The average displacement of FNA of thyroid nodules under ultrasound guidance is an auxiliary index for diagnosing benign and malignant nodules, and is expected to be an effective qualitative index for pathologically ambiguous nodules.