The relationship between surface properties and water vapor absorption performance was studied according to crystal structure and surface free energy of purified palygorskite. The results show that the unit cell volume of samples increases along with the increase of temperature ranging from 0 to 200 °C, leading to the increase of water vapor absorption. The intensity of diffraction peak, crystal plane spacing and unit cell volume decrease with the increase of the heat temperature ranging from 200 to 800°C, leading to the decrease of water vapor absorption. The intensity of diffraction peak almost disappears when the temperature is over 800°C. The palygorskite turns into non-crystallization, and the new phase of diopside appears. The surface free energy and polarity component increase along with the increase of heat-treatment temperature, and the dispersion component is obviously relevant to water vapor absorption performance.