Calcium carbonate whiskers were prepared from dolomite by gas-liquid contact method. The effect of calcination on the decomposition of dolomite was studied. At the same time, the preparation and mechanism of calcium carbonate whiskers were studied. The results showed that dolomite had the best decomposition effect at the calcination temperature of 850 ℃, the heating rate of 10 ℃/min and the calcination time of 4 h. The reaction temperature, aeration rate and stirring rate have significant effects on the formation of calcium carbonate whiskers.