Abstract: Large ring cyclodextrin (LR-CD) had properties of high solubility, low viscosity, anti-retrogradation and so on, which was superior to the common cyclodextrins (α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin) , however, there was very little reports are about the application of LR-CD.In this text, nystatin was as guest molecules, the inclusion properties of large ring-cyclodextrin on nystatin was investigated.Results showed that the phase solubility curve for LR-CD was AL type, and the embedding constant was 1.577L/mmol for LR-CD, it was much larger than that of α-cyclodextrin, β-cyclodextrin andγ-cyclodextrin (0.375L/mmol and 0.539L/mmol) , the solubility enhanced by saturated large ring-cyclodextrins was predicted as 2958.87 folds, the identification by infrared spectrum (IR) indicated that the ester linkage and diene were included in the cavity of cyclodextrin, while conjugate arachidonic, carboxyl and amino group were left outside of cyclodextrins.