The invention relates to a hollow structure potassium magnesium titanate whisker material and a method for preparing the same. The technical scheme is that the method comprises evenly mixing a titanium-containing raw material, a magnesium-containing raw material and a binding agent, performing forming, performing heat treatment and then grinding the mixture to obtain a material A with the particle size of 0.088-1 mm and a material B with the particle size smaller than 0.088 mm; evenly mixing a potassium-containing raw material, a titanium-containing raw material and a binding agent, performing forming, performing heat treatment and then grinding the mixture to obtain a material C with the particle size smaller than 0.088 mm; evenly mixing the material A, the material B, the material C and a potassium-containing raw material, performing heat treatment and then grinding the mixture to obtain a ground material; finally adding the material C, the potassium-containing raw material and water to the ground material, mixing the mixture, pressing the mixture into green bodies, drying the green bodies, performing heat treatment, and then performing washing, filtration and drying to obtain the hollow structure potassium magnesium titanate whisker material. The external diameters of whiskers of the prepared hollow structure potassium magnesium titanate whisker material are 0.1-5 microns, the internal diameters of the whiskers are 0.05-1 micron, and the lengths of the whiskers are 3-30 microns. The hollow structure potassium magnesium titanate whisker material is high in crystallinity and uniform in size.