The solubility of trehalose in a water + ethanol solvent system was measured with the mole fraction of water ranging from 0.000 to 1.000 at temperatures from (288.15 to 318.15) K using the gravimetric method. There was a minimum point on each solubility curve at the mole fraction of water ranging from 0.040 to 0.050. The differential scanning calorimetry measurement results show that anhydrous trehalose (a white flocculent precipitate) appeared in the suspension at water content lower than the critical point. While higher than that point, the crystals in the slurry were still hydrous polymorph which is apparently different from the anhydrous one. The solubility data at water content lower and higher than the critical points were nonlinear surface fitted separately using the combination version of the Jouyban-Acree and van't Hoff models which is a three-dimensional (3D) model. The average relative deviation (ARD) values for trehalose solubility at water content lower and higher than the critical point were 25.71 % and 11.62 %, respectively, which shows the model fitted the data well especially for the latter.