<b><i>Objectives:</i></b> The objectives of this study were to explore the clinical heterogeneity of differentiated thyroid cancer (DTC) between prepubertal children and adolescents and guide clinical treatment. <b><i>Methods:</i></b> A retrospective study included patients with DTC aged ≤19 years in Beijing Children’s Hospital from June 2014 to June 2019. All patients were enrolled and divided into 2 subgroups based on the threshold age of 10 years, namely the childhood group (CG) (≤10 years old); and the adolescent group (AG) (between 10 and 19 years old). The χ<sup>2</sup> test and Fisher’s exact test were used to estimate the effect of risk factors in the 2 age groups. Multivariate binary logistic regression models were conducted to assess the recurrent risk factors. <b><i>Results:</i></b> Seventy cases of DTC were included with an average age of 9.94 ± 2.88 years, including 35 in CG and 35 in AG. The most common clinical manifestation was a painless mass in the neck, accounting for 77.1% (54/70) of patients. Compared with the AG, the CG was more likely to have lymph node metastasis (<i>p</i> = 0.022) and distant metastasis (<i>p</i> = 0.041). The CG was more likely to have extrathyroidal extension (<i>p</i> = 0.012) and had a significantly higher recurrence rate than the AG (<i>p</i> = 0.040). Age was an independent variable predictive of recurrence (<i>p</i> = 0.0347). <b><i>Conclusion:</i></b> Regional invasiveness, cervical lymph node metastasis, and distant metastasis of DTC were more likely to occur in children ≤10 years old. Meanwhile, children ≤10 years old with DTC were more likely to have recurrence than adolescent’s postsurgical treatment. Thus, children younger than 10 years of age with DTC should be treated more aggressively.