We compared the proportions and differences in the polysaccharides of Tremella fuciformis (Berkeley) after drying them by various processes, such as 18 °C cold air, 50 °C hot air, and freeze-drying. We also focused on the moisture capacity kinetic parameters of Tremella fuciformis polysaccharides using various thermal analyses, including differential scanning calorimetry and thermogravimetric techniques. Erofeev’s kinetic and proto-kinetic equations, utilized for kinetic model simulation, can predict the moisture capacity due to the thermal effect. Among the various drying processes, cold air-drying had the highest molecular weight of 2.41 × 107 Da and a moisture content of 13.05% for Tremella fuciformis polysaccharides. Overall, the freeze-dried products had the best thermal decomposition properties under the conditions of a closed system, with an air or nitrogen atmosphere, and had an excellent moisture capacity of around 35 kJ/kg under a closed system for all samples.