Blends was prepared from polycaprolactone(PCL)/master batch(MB). The major component of MB is calcium carbonate(CaCO₃). Wheatherability, biodegradability, thermal properties, mechenical properties and water absorption were investigated. The biodegradability increased as the content of MB increased. Strength and elongation at break decreased but modulus comparatively maintained as the time of outdoor exposure increased. The mechenical properties decreased as the content of MB increased. The melting temperature of PCL/MB blends was about 57℃ and the water absorption of PCL/MB and PCL were similar.