Pure K2Ti4O9 whiskers were prepared by KDC (Kneading-Drying-Calcination) method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio (RT/K), calcination temperature (TC) and cooling process on phase composition and morphology of the whiskers were investigated by TG-DSC (thermo gravimetric-differential scanning calorimeter), XRD (X-ray diffraction), and SEM (scanning electron microscope). Pure K2Ti4O9 potassium titanate whiskers with large length-diameter ratio (r) (over 250) can be obtained at RT/K=2.9 and TC=950℃.