In this study, tantalum nitride (Ta5N6) whiskers were successfully prepared by carbothermal reduction and nitridation method under amonia flow atmosphere, using tantalum oxide (Ta2O5) and active carbon as the main raw materials, potassium fluoride (KF) as the molten salt. The compositions, structures and morphology of the whiskers were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). The effects of heat mode, nitridation atmosphere, nitridation time and catalyst content on the formation of whiskers were investigated. The whiskers have the best morphology when the molar ratio of Ni/Ta=0.1, nitridation atmosphere is amonia (300 mL/min) and nitridation time is 6 h. The whiskers have diameters of 80-250 nm and lengths of 1-5 μm, and a combined mechanism of vapor-liquid-solid (VLS) and vapor-liquid (VS) is responsible for the growth of Ta5N6 whiskers.