The present invention provides a kit for detecting chronic sinusitis with a subtype of nasal polyp and an application of a CLC gene or protein as a biomarker, a method for detecting a CLC gene expression quantity in nasal cavity exfoliated cells and an application, and an ELISA kit for detecting chronic sinusitis with a subtype of nasal polyp and a preparation method thereof. The present invention further provides use of a CLC gene or protein as a biomarker for detecting chronic sinusitis with a subtype of nasal polyp. The method for detecting chronic sinusitis with a subtype of nasal polyp in the present invention comprises measuring a CLC gene expression quantity by using a PCR of a specific primer of the CLC gene, especially a real-time fluorescent quantitative PCR, or measuring a CLC protein expression quantity by using an anti-CLC antibody, especially ELISA of a mouse anti-human CLC monoclonal antibody.