The crystallization behaviours from the glassy state and the melt of PET/PPG copolymer filled with additives were investigated . The overall rate of crystallization was measured by differential scanning calorimetry and the increase of density of the samples measured by the buoyancy method, was used to follow the crystallization progress. The results were analyzed by the crystallization parameters Tcc (crystallization temperatures from the melt state), Tch (crystallization temperatures from the glassy state), Tcc-Tch, Tm-Tcc (Tm : melting temperature), half time of crystallization, rate constant, Avrami exponent, degree of crystallization. Talc, kaolin, TiOa, crystalline SiOa, amorphous SiOa, and Cac03 were used as fillers and sodium stearate and tritolyl phosphate used as lubricant. The filler and the lubricant acting as most effective nucleating agents for PET/PPG copolymer were talc and sodium stearate and their suitable contents were 0.6 nVo and 0.3 wt% per weight of copolymer, respectively. Tcc-Tch values of PET/PPG copolymer were lower than them of PET, but the values of the copobymer filled with additives were much greater than PET filled with them. It has found that the crystalliration rate has been greatly increased by combining the factors acting as effective increase of crystallization rate.