Objective To explore the relationship between round occipital hyperplasia and allergic rhinitis after adenoidectomy in children. Methods The selected samples had undergone adenoidectomy (with or without tonsillectomy), and 142 patients were randomly selected among those diagnosed with allergic rhinitis and set up as group A. 173 patients were randomly selected among those whose diagnosis of allergic rhinitis was excluded after examination and set up as group B. The results were summarized as follows. The intraoperative and postoperative hyperplasia of the round pillows in the 2 groups was observed. Results Circular occipital hyperplasia was significantly higher in group A than in group B (P < 0.05). Conclusion Allergic rhinitis is the main factor causing round occipital hyperplasia after adenoid surgery in children, which is of clear significance in guiding further treatment after adenoid surgery.