Objective To evaluate the efficacy of sequential dose reduction of intranasal corticosteroids (INCS) after endoscopic sinus surgery in the treatment of chronic rhinosinusitis with nasal polyps (CRSwNP). Methods A total of 96 patients with CRSwNP admitted to Luoyang Central Hospital from May 2023 to May 2025 were selected and divided into a control group (48 cases, fixed-dose INCS) and a study group (48 cases, sequential dose-reduction INCS) by lottery method. Efficacy indicators [Lund-Kennedy endoscopic score (LKES), Lund-Mackay CT score (LMCTS), visual analogue scale (VAS)], adverse reactions, recurrence rate within 6 months after treatment, and quality of life [sino-nasal outcome test-20 (SNOT-20) score] were compared between the two groups. Results After 12 weeks of treatment, LKES, LMCTS, VAS, and SNOT-20 scores in the control group were lower than those in the study group (all P＜0.05); after 24 weeks of treatment, there were no significant differences in LKES, LMCTS, VAS, and SNOT-20 scores between the two groups (all P＞0.05); the incidence of adverse reactions in the study group was lower than that in the control group (P＜0.05); there was no significant difference in the recurrence rate within 6 months after treatment between the two groups (P＞ 0.05). Conclusion With the extension of treatment time, sequential dose reduction of INCS for CRSwNP has similar efficacy to fixeddose INCS, with fewer adverse reactions and no increased risk of recurrence.