OBJECTIVE To explore the clinical effect of radical endoscopic sinus surgery(RESS)in the treatment of eosinophilic chronic sinusitis with nasal polyps(EosCRSwNP).METHODS There were 84 EosCRSwNP patients admitted to the Department of Otolaryngology in Tianjin Beichen Hospital from January,2020 to January,2022.They were divided into an observation group(42 cases)and a control group(42 cases)according to the random number table method.The control group and the observation group received functional endoscopic sinus surgery(FESS)and RESS respectively.The nasal visual analogue score(VAS)and Lund-Kennedy score were compared before surgery and in 1,3,and 12 months after surgery,and the olfactory threshold in 6 months before and after surgery,Ciliary clearance rate,ciliary clearance rate,and serum interleukin-1β(IL-1β),IL-35 and squamous cell carcinoma antigen(SCCA)levels were compared between the two groups.The recurrence rates in 12 months between the two groups after surgery.RESULTS The VAS and Lund-Kennedy scores of the observation group were lower than those of the control group in 12 months after surgery(P＜0.01);The olfactory threshold and serum IL-1β in 6 months after surgery,the level of SCCA of the observation group was lower than those of the control group(P＜0.01),and the Cilia clearance speed,the clearance rate and serum IL-35 level were higher than those of the control group(P＜0.01).The recurrence rate in 12 months of the observation group was lower than that of the control group(P＜0.05).CONCLUSION RESS is beneficial for reducing nasal VAS and Lund-Kennedy scores,alleviating nasal inflammation,restoring olfactory and nasal mucosal function,and reducing postoperative recurrence rate.It can be used as the optimal surgical plan for EosCRSwNP.