Objective To explore the relationship between torus tubarius hypertrophy after adenoidectomy and allergic rhinitis in children. Methods Adenoidectomy (with or without tonsillectomy) was performed in all the selected patients, and 142 patients diagnosed with allergic rhinitis were randomly selected as group A. Among the patients who were excluded from the diagnosis of allergic rhinitis after examination, 172 were randomly selected and set as group B. The intraoperative and postoperative torus tubarius hypertrophy was observed in both groups. Results The follow-up of nasal endoscopy/electronic nasopharyngoscope 3 months after surgery revealed that the number of mild hyperplasia of round pillow increased significantly, and the degree of hyperplasia was significantly worse than those in the first 2 months, even showing severe hyperplasia and obvious blockage of the posterior nostrils. The number of cases of round pillow hyperplasia in group A (27 cases) was significantly higher than that in group B (18 cases), and the difference was statistically significant (χ²=4.630, P<0.05). Conclusion Allergic rhinitis is the main factor causing torus tubarius hypertrophy after adenoid surgery in children, which has clear significance in guiding the further treatment after adenoid operation.