Polyester microfiber fabrics were decomposed at 100, 110, 120 and 140 ? of temperature and 0.5, 1.0 and 1.5% of sodium propyleneglycolate/propyleneglycol solution(SPG-PG). Characteristic decomposition feature and physical and chemical properties of the decomposed PET microfiber fabrics were discussed. The activation energy was 18.77 kcal/mol and the dyeability of the decomposed PET microfiber fabrics was found to be improved as it was supported by the examined K/S values. Up to the 20% of the weight loss of the PET microfiber fabrics, K/S values incresed with increasing the weight loss. The melting temperature of PET microfiber fabrics decomposed by SPG-PG showed no fundamental change. Tensile strength of the decomposed PET microfiber fabrics decreased linearly in accordance with the increased the weight loss of the PET microfiber fabrics. The moisture regain and the tactilities increased in accordance with the increased the weight loss of the PET microfiber fabrics.