Objective Exploring the efficacy of the combination of bencycloquidium bromide and levocetirizine in the treatment of moderate to severe allergic rhinitis (AR) and its impact on inflammatory factors. Methods? Select 100 patients with persistent moderate to severe AR and randomly divide them into a monotherapy group (n=50) and a combination group (n=50). The monotherapy group was given oral levocetirizine, while the combination group was treated with bencycloquidium bromide nasal inhalation in addition to oral levocetirizine. Both groups were treated for 4 weeks. Compare the visual analog scale (VAS) scores of two groups before treatment and at 2 and 4 weeks of treatment, and collect venous blood from patients to measure serum levels of inflammatory factors (IL-1 β, IL-4, IL-6) before and after 4 weeks of treatment. Simultaneously record adverse reactions. Results Before treatment, there was no statistically significant difference in VAS scores and serum inflammatory cytokine levels between the monotherapy group and the combination group (P>0.05). Compared with before treatment, the VAS scores and serum inflammatory cytokine levels in both groups decreased after treatment; After 2 weeks of treatment, the VAS score, sneezing, itching, and rhinirrhea score of the combination group were lower than those of the monotherapy group, and the difference was statistically significant (P<0.05); After 4 weeks of treatment, the VAS score, sneezing, itching, rhinirrhea, congestion score, and serum inflammatory factor (IL-1 β, IL-4, IL-6) levels in the combination group were lower than those in the monotherapy group, and the differences were statistically significant (P<0.05). No serious adverse reactions occurred during the treatment period in either group. Conclusions The combination of bencycloquidium bromide and levocetirizine is more effective in treating moderate to severe AR than levocetirizine alone, without increasing adverse reactions.