BaCO_3 whiskers exhibiting different morphologies were fabricated by a simple precipitation reaction of barium chloride with sodium carbonate in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA) as a crystal growth modifier at room temperature. The as-prepared products were characterized by scanning electron microscopy (SEM),transmission electron microscopy (TEM),and X-ray diffraction (XRD). The influences of experimental parameters on the size and morphology of BaCO_3 whiskers were investigated and discussed. It was found that the as-prepared BaCO_3 whiskers are single crystals with diameter ranging from 100 to 300?nm,and grow along the crystallographic a-axis or [100] direction. BaCO_3 whiskers with different morphologies,such as branching and dendritic structure,can be obtained depending on the experimental conditions. With increasing PSMA concentration,the diameter of BaCO_3 whiskers decreases. BaCO_3 whiskers exhibiting different morphologies were fabricated by a simple precipitation reaction of barium chloride with sodium carbonate in the absence and presence of poly- (styrene-alt-maleic acid) (PSMA) as a crystal growth modifier at room temperature. The as-prepared products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The influences of experimental parameters on the size and morphology of BaCO 3 whiskers were investigated and discussed. It was found that the as-prepared BaCO 3 whiskers are single crystals with diameter ranging from 100 to 300 nm, and grow along the crystallographic a-axis or [100] direction. BaCO 3 whiskers with different morphologies, such as branching and dendritic structures, can be obtained depending on the experimental conditions. With increasing PSMA concentration, the diameter of BaCO_3 whiskers decreases.