Calcite was used as raw material, the prepared heavy magnesium water (Mg(HCO3)2) and the intermediate product calcium chloride were used to prepare aragonite calcium carbonate whiskers, and the products were characterized by SEM, XRD and EDS. The effects of reaction temperature, reaction time, concentration ratio of magnesium to calcium, concentration of heavy magnesium water and stirring speed on the morphology of calcium carbonate whiskers during the reaction of heavy magnesium water and calcium chloride were explored. The best process conditions are obtained through single factor experiments: temperature of 40 ℃; reaction time of 2 h; magnesium-calcium concentration ratio of 6∶1; heavy magnesium water concentration of 0.14 mol/L; stirring speed of 150 r/min. Under these conditions, aragonite calcium carbonate whiskers with a length of 40~65 μm, a diameter of 0.6~1.5 μm, and an aspect ratio of 25~45 were prepared.