This study proposed a method for inverse phase transformation of stable γ-glycine into metastable α-glycine by using the characteristic that solubility increases as crystal size decreases according to the Ostwald-Freundlich equation.First, we measured the change in solubility according to the particle size of glycine.The solubility of γ-glycine bulk crystals at 10°C in water was 173 g/L, and when the crystal size decreased to about 0.9μm, the solubility increased to about 185 g/L.This concentration was higher than the solubility of α-glycine bulk crystals, 180 g/L.Based on the above results, γ-glycine can be inverse transformed into α-glycine in aqueous solutionTo demonstrate this inverse transformation, in a glycine solution, γ-glycine crystals with a size of about 2μm were ground with glass beads for 24 h to reduce the crystal size to about 0.8μm.And the concentration of the solution was made higher than the solubility of α-glycine bulk. α-Glycine bulk crystals (about 110μm) were placed into this solution and grown to 170μm.Through this, inverse phase transformation was achieved in which γ-glycine crystals were dissolved and α-glycine crystals grew.The above inverse phase transformation process was confirmed using a microscope, XRD, and ATR-FTIR.