Gaet growth in the early stage of the trachybasalt-eclogite transformation was observed at 2.0 GPa and temperatures of 860 ℃, 940 ℃ and 1020 ℃ for annealing times of 0.66 - 13.6 h. The grain size was determined optically to be increased with increasing annealing time. The growth rate decreased with increasing grain size. The gaet growth law was G2.46 = 5.65 × 10-15texp[-27.40 × 103/RT], where G represents the average grain size after annealing time t, R is the gas constant and T is the absolute temperature.