Ultrafine ground calcium carbonate (GCC) produced by carbonate minerals is a widely used inorganic powder material. In order to get a finer GCC powder with narrow distribution span, effects of rotation speed and media density on particle size distribution and structure of GCC were studied. The grinding limit-particle size and distribution of GCC were measured by centrifugal sedimentation granulometer. The specific surface area, average particle size and structure of ground GCC were characterized by X-ray diffraction (XRD) and BET. The morphology of particles was observed by a scanning electron microscope (SEM). The result shows that low rotation speed and high-density media are conducive to obtaining a smaller particle with narrower size distribution. The crystal plane (012) and (122) of GCC are more stable than (018) and (202). (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.