Abstract: Using carbonization method and double decomposition method，nano-sized calcium carbonate（CaCO₃） with different morphologies and sizes were prepared by selecting proper additives and controlling the amounts of added additives.The morphologies and sizes of products were characterized by TEM and SEM.Results showed that the control of the particle size of nano-sized CaCO₃ was realized by controlling the adding amounts of citric acid at 0.25%~0.75% （mass fraction，same below）.Moreover，the synthesized CaCO₃ was modified by sodium stearate and the modified sample particles became larger，more regular and homogeneous in shape，and better in disperse ability.Spherical and cubic nano-sized calcium carbonate with different particle sizes was obtained when the adding amounts of pentaerythritol were at 0.1%~10%.Moreover the influences and action mechanism of organic acids，sugars，and alcohols on the synthesis of nano-sized CaCO₃ were discussed.

Key words: nano-sized calcium carbonate, additive, morphology and size control, action mechanism