The work aims to obtain the corresponding temperature range and the relationship between desorption temperature and desorption time when the fine porous spherical silica gel is completely desorbed and activated, so as to provide certain reference for setting the parameters of desorption activation process. The water was absorbed adequately by fine porous spherical silica gel at a certain temperature and humidity through the high and low temperature and humidity test box. Then, the desorption performance of the fine porous spherical silica gel under two-layer stacking state was tested by the electrothermal blast drying box at a specific temperature to obtain the desorption performance curve and analyzed according to the curve. The temperature range corresponding to the complete desorption activation of fine porous spherical silica gel under two-layer stacking state and the relationship between desorption temperature and desorption time were obtained. The optimum desorption activation temperature range of fine porous spherical silica gel further obtained was 120~130 ℃. Some reference value for the desorption activation process parameters of the fine porous spherical silica gel is provided through the desorption performance analysis on the desorption curves of fine porous spherical silica gel obtained by experiment.