Mixed echoes behind a thyroid nodule is a description of the ultrasound findings, which generally refers to a mixture of several echo types behind the nodule. Relying solely on the mixed posterior echoes of a thyroid nodule cannot confirm the nature of the thyroid nodule, but needs to be combined with the size of the nodule, blood flow, the presence of calcification to determine the benign or malignant nature of the nodule, and, if necessary, a puncture biopsy can be performed. Posterior echogenicity of thyroid nodules refers to the change in the level of posterior echogenicity of the nodule, which reflects the attenuation characteristics of the nodule. Posterior echogenicity usually consists of 4 types, namely, enhancement, attenuation, no change, and mixed changes. There is a paucity of literature dealing with posterior echogenic features of nodules. Malignant nodules have a higher rate of posterior acoustic attenuation compared to benign nodules. Lymphomas often show posterior echogenic enhancement. Patients with mixed posterior echogenicity of thyroid nodules are advised to go to a regular hospital and receive standardized treatment under the guidance of a specialist to avoid delays.