Objective:To explore the influnces of allergen sIgE and peripheral blood eosinophilic(EOS) on the severity and surgical outcomes in patients with chronic rhinosinusitis with nasal polyps(CRSwNP). Method:Eighty-nine patients with CRSwNP were enrolled. Before operation, allergen sIgE levels and peripheral blood EOS were detected.All patients were examined paranasal computed tomography(CT). After 3 and 6 months of operation, all patients were examined by nasal endoscopy,Allergen sIgE, peripheral blood EOS, nasal endoscopy score, and CT score were retrospective analyzed. According to the results of allergen sIgE the subjects were divided into two groups: the positive allergens group and negative allergens group. Result:Allergen sIgE were positive in 49 patients(the positive allergens group) and negative in 40 patients(the negative allergens group). The major allergens were Dermatophagoides pteronyssinus(39 patients) and cockroach(16 patients). Between the positive allergens group and the allergens negative group, there were no statistically significant differences in peripheral blood EOS count and EOS percentage and CT scores and nasal endoscopy scores of 3-month postsurgery(P>0.05). There was signifigant diference in the nasal endoscopy scores of 6- month postsurgery between the two groups(P<0.05). In the 89 patients with CRSwNP, peripheral eosinophil count showed no significant correlation with CT image scores and 3-month postsurgery nasal endoscopy scores and 6-month postsurgery nasal endoscopy scores(r=0.119,0.180,0.126,P>0.05). Blood eosinophil percentage was not significantly correlated to CT image scores and 3-month postsurgery nasal endoscopy scores and 6-month postsurgery nasal endoscopy scores(r=0.167,0.263,0.140,P>0.05). Conclusion:Allergen sIgE has some impacts on postoperative outcomes but has no impact on the severity of CRSwNP. Peripheral eosinophil may not affect the severity and surgical outcomes of CRSwNP.