To investigate the ultrasonographic features of benign and malignant thyroid tumors in children. Methods A retrospective analysis of 178 children with thyroid tumors confirmed by pathology was performed, and the sonographic manifestations of the two groups of benign and malignant thyroid tumors were analyzed. Results In this study, the age of children with benign tumors was 10-18 years old and the age of children with malignant tumors was 9-18 years old. There were 56 girls and 8 boys with benign tumors and 89 girls and 25 boys with malignant tumors. There were significant statistical differences between benign and malignant tumors in size, multiple/single, internal components, internal echoes, margins, aspect ratio, with or without halo, glandular background echo and blood supply. The area under the curve, sensitivity and specificity of solid, hypoechoic, marginally irregular and microcalcifications for the diagnosis of thyroid malignancy were 0.735, 96.5%, 62.5%, 0.785, 93.9%, 64.5%, 0.910, 86.7%, 95.3%, 0.920, 86.8%, 98.4%. Conclusion Children with thyroid tumors are more common in girls, and the sonographic manifestations of benign and malignant tumors have certain characteristics. Solid, hypoechoic, irregular margins, and microcalcifications are malignant sonographic signs of thyroid tumors in children