Abstract: The thermal desorption behaviors of cyclopentane and cyclohexane in silicalite-1 was studied by using IGA and TG/DTG mehods. Only one thermal desorption course was observed in TG profiles when the initial adsorption loading of cyclopentane in silicalite-1 is lower than 4 m/uc. However, two obvious thermal desorption courses appeared in TG profiles when the initial adsorption loadings is higher than 4 m/uc. And there is an inflection at about 4 m/uc on the TG curves. The DTG profiles of cyclopentane exhibited two distinctive peaks separated each other. Only one thermal desorption course for cyclohexane in silicalite-1 appeared and the DTG profile show only one peak. From the thermal desorption profiles of cylopentane and cyclohexane, it can be seen that the desorption peaks move to higher temperature with the increase of the initial adsorption loadings. The temperature of desorption peak for cyclohexane is higher than that for cyclopentane at the same loading.