Abstract: The interaction of natamycin with large-ring cyclodextrins (LR-CD) was studied.The enhancing effect of LR-CD on the solubility of natamycin was investigated by the phase-solubility diagram.Thermodynamic parameters in the complexation were obtained.The formation of the inclusion compound was confirmed by UV-Visible spectra, FTIR absorption spectra.The results showed that the solubility of natamycin increased in aqueous solutions with added LR-CD and the phase solubility diagram exhibited negative deviation from linearity with the increase in LR-CD concentration, showing type A N diagram.Analysis of the thermodynamic dates preliminarily inquired into the main driving force of the inclusion complexation.The formation of the inclusion complex was confirmed by UV-Visible and Fourier Transform Infrared Spectroscopy (FTIR) .