Objective To compare the clinical effect of bencycloquinium bromide nasal spray and mometasone furoate nasal spray in patients with moderate to severe allergic rhinitis (AR). Methods Two hundred patients with moderate to severe AR treated from May 2022 to August 2023 were selected and divided into groups according to random number table method. One hundred patients in the control group were treated with mometasone furoate nasal spray, and 100 in the study group were treated with phenylcycloquine ammonium bromide nasal spray. The clinical efficacy, nasal symptom scores, quality of life and adverse reactions of the two groups were compared. Results The total effective rate of the study group was higher than that of the control group (93.00% vs 82.00%，χ²=5.531,P=0.018). The scores of nasal congestion, sneezing, nasal itching, runny nose, and rhinitis quality of life questionnaire (RQLQ) after 4 weeks of treatment in both groups were lower than those before treatment, and the decrease was more significant in the study group (P<0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (7.00% vs 3.00%，P>0.05). Conclusions Both phencycliquium bromide nasal spray and mometasone furoate nasal spray can achieve good therapeutic effect in the treatment of moderate to severe AR. In comparison, the former has better effect, can rapidly improve the symptoms of patients, and is conducive to improving the quality of life.