Abstract: Morphology and structure of saccharide modified CaCO_3 nanoparticles,prepared by the liquid carbonization method,were studied using the TEM(transmission electron microscopy) and XRD(X-ray diffraction) techniques.Straight chain saccharide additives(monosaccharide,disaccharide,oligosaccharide and polysaccharide),which only affected the nucleation mechanism of CaCO_3 nanoparticles,resulted in cube shaped nanoparticles.Cyclic saccharide additives,which affected both the nucleation and growth of the nanoparticles,resulted in CaCO_3 nanoparticles of many shapes(ball,flake,needle,spindle,cube and others).