DFT is a decisive tool for determining the structure of small organic molecules. The inclusion properties of 1-methylnephthlene with β-Cyclodextrin were examined in this study. Several methods were used to further analyse the inclusion compound that was finally prepared. The results indicated that the peak position of β-CD shifted after inclusion, and the ratio of β-CD to 1-methylnephthlene was determined to be 1:1.