Abstract: The chemical bonding theory is used to investigate the fundamental crystallization behaviours of magnesium carbonate hydrate crystals Mg5(CO3)4OH)2·4H2O and MgCO3·3H2O in terms of crystallographic structure, with the aim to guide and control the practical crystal growth. The ideal morphology of Mg5(CO3)4(OH)2·4H2O and MgCO3·3H2O crystals has readily been predicted, by calculating the vertical growth rate of selected planes in terms of the bond number and bond strength. Theoretically,Mg5 (CO3)4(OH)2·4H2O crystal exhibits hexagonal plate-shaped characteristics, while MgCO3·3H2O crystal possesses a hexagonal prism morphology. Experimentally, the hexagonal Mg5(CO3)4(OH)2·4H2O micro-platelets and MgCO3 ·3H2O micro-prisms with reproducible shape can be obtained by a simple liquid phase reaction. Theoretical results are in a good agreement with our experimental observations. Single crystal growth can be improved by tuning the bonding modification of constituent atoms or ions, such a process can leave us a great space to kinetically maximize our experimental strategies.