Indusion effect of beta-CD with menthol was studied by three methods of preparation. Determination of physical constants and quantitative analysis proved that the inclusion compounds of beta-CD with menthol were formed, which was found to be 1:1 and 2:3. The results of thermal analysis demmonstrated that the gasifiation temperature of the inclusion compounds was by far higher than that of the free menthol. It was considered that the inclusion compound must be disconnected to be free, and then it can be determined by gas chromatography in the same condition of the free menthol.