The drying characteristics (critical moisture content, equilibrium moisture content, constant drying rate and effective diffusivity) of various particles (gypsum, millet, polyvinyl chloride and silica gel) using a thermogravimetric analyzer were measured. The experiments were performed in the gas temperature range of 40 to 100 ℃ under isothermal conditions. The drying rate curve was mainly dependent on the moisture content, particle size, gas temperature and the internal structure of the solid particles. The equilibrium moisture content of solid particles decreased with increasing gas temperature, while the critical moisture content and the effective dispersion coefficient increased with increasing gas temperature. The effective diffusion coefficients of both PVC and gypsum particles were not able to be determined by Fick’s law since the experimental data were not well matched with the model predicted values, which consisted of the drying time in the falling-rate drying period.