The comet’s tail sign is an ultrasound description of a thyroid nodule, which suggests that the thyroid nodule is accompanied by gross calcification. If the ultrasound examination of thyroid nodules reveals that there are obvious strong echoes in the thyroid nodules, accompanied by posterior acoustic shadows, it will be described as a comet’s tail sign, and the corresponding condition mainly suggests that there is coarse calcification in the thyroid gland, and the probability that the corresponding nodules are benign is relatively high, but it is necessary to combine the morphology of the thyroid gland, density, margins, and the aspect ratio to determine the overall situation. If the nodule is benign, it can be followed up regularly; if the nodule is malignant, further puncture biopsy is needed to make a clear diagnosis. Thyroid nodules with comet’s tail sign need to go to the hospital in time, under the guidance of clinicians for standardized treatment.