Objective To investigate the clinical efficacy and acting mechanism of mometasone furoate on the children with perennial allergic rhinitis. Methods A total of 178 children with perennial allergic rhinitis treated in our hospital were randomly divided into the experimental group and the control group, with 89 patients in each group. The experi-mental group received intranasal inhalation of mometasone furoate and the control group received oral administration of loratadine. Both groups were treated for 4 weeks. The rhinitis symptom scores and children's rhinoconjunctivitis related quality of life questionnaire (RQLQ) scores of the two groups before and after treatment were compared, and the serum interleukin-2 (IL-2), interleukin-4 (IL-4) and interleukin-5 (IL-5) levels of both groups were detected. Results After 4 weeks of treatment, the experimental group was significantly lower than the control group in the nasal congestion, nasal itching, throat itching and total symptom scores (P<0.05), and was also lower than the control group in the RQLQ scores such as nasal symptom, practical problem, other symptom and total scores (P<0.05). The experimental group had significantly higher IL-2 level and significantly lower IL-4 and IL-5 levels than the control group, with statistically significant differences (P<0.05). Conclusion Mometasone furoate can effectively control the clinical symptoms of children with perennial allergic rhinitis and has better overall efficacy than oral loratadine; its acting mechanism may be related to the regulation of Th1 and Th2 cell imbalance.