The preparation and characterization of n-alkane/water emulsions using beta-cyclodextrin (beta-CD) were studied. The prepared n-alkane/water emulsions were of the oil-in-water (O/W) type, and the stability of emulsions was in the order of n-hexadecane > n-dodecane > n-octane. From observations using polarized light microscopy and powder X-ray diffraction measurement, it was suggested that the formation of a dense film at the oil-water interface and the three-dimensional structural network created by precipitated complexes in the continuous phase are associated with the stability of emulsion. Furthermore, it was clarified that O/W-type emulsions were formed because the contact angle (theta ow) which the precipitate makes with the interface was theta ow < 90 degrees in all compounds (oils) used in this study.