This study aimed to summarise the clinical features and management strategies concerning auditory canal duplication anomalies in children with congenital first branchial cleft anomalies (CFBCAs), and to provide guidance for precise treatment. We retrospectively analysed 84 children with CFBCAs who had complete data, diagnosed between December 2018 and February 2024. All the lesions identified were located around the external auditory canal or near the mandibular angle, manifested as pinhead-sized perforations in 10 cases, painless masses in 18 cases, recurrent swelling and pain with purulent discharge in 52 cases, and otorrhea in 4 cases. Otoscopy examinations revealed external auditory canal swelling in seven children, fistulas within the auditory canal in four children, and a myringa web in three children. Fifty-six children had a preoperative history of infection. Using Work's classification system, Work I and II in 70 (87.5%) and 14 (12.5%) children, respectively. Intraoperatively, 80 (95.2%) children had auditory canal duplication anomalies at the base of the lesion, closely associated with the cartilage of the inferior wall of external auditory canal(EAC), We then classified auditory canal duplication anomalies into three types: Type A (duplication anomalies of epithelial tissue structure between the skin of the EAC and the cartilage of the inferior wall, n = 16 children), Type B (duplication anomalies of the epithelial and/or skin tissue structure, sharing a wall with the cartilage of the inferior wall, n = 40), and Type C (duplication anomalies of the skin and cartilage tissue structure, connected to the cartilage of the inferior wall of EAC, n = 24). Sixty-eight children had lesions superficial to the facial nerve, 12 had lesions deep to the facial nerve, and four had lesions between branches. There were two cases of transient postoperative facial paralysis, three cases of CFBCA recurrence, and two cases of transient auditory canal stenosis. Auditory canal duplication anomalies are an important feature of first branchial cleft anomalies in children. Precise staging and accurate identification of the base of the lesion facilitate complete removal, thereby increasing the cure rate.