The treatment of eosinophilic sinusitis with nasal polyps is difficult and challenging. After endoscopic sinus surgery(ESS), complications such as edema, scar formation, adhesions, sinus stenosis and recurrence of polyps are prone to occur. Investigators aim to assess the efficacy and safety of Steroid-eluting stent when implanted in sinus in patients following ESS with eosinophilic sinusitis and nasal polyps.The randomized, double-blind, controlled clinical trial enrolled patients with eosinophilic sinusitis and nasal polyps. After endoscopic bilateral sinus surgery, the Steroid-eluting stents were randomly implanted in one side of the sinus and the other side as a control. Primary outcomes are change in the Lund-Kennedy endoscopic score.The primary outcomes will be measured in baseline, week4,week 8 and week 12. Secondary outcomes include the changes in symptoms measured by Visual analog score and nasal patency (nasal airway resistance and nasal cavity volume), exhaled nasal nitric oxide. The investigators also evaluate change in inflammatory cytokines (interleukin(IL)-4, IL-5, IL-8, IL-17, IL-22, IL-25, interferon-γ, tumor necrosis factor-α, transforming growth factor-β, Leukotriene,Eotaxin) in nasal secretions. The secondary outcomes will be measured in baseline, week4, week8 and week12. Mucosal pathology assessment will be performed at 4 weeks postoperatively.Sinus CT scan will be conducted at 8 weeks after surgery. Changes in serum cortisol are monitored at baseline,week4 and week12 postoperatively. All adverse events are recorded throughout the experiment