The invention discloses porous hydroxyapatite biological ceramic and a preparation method thereof. The porous hydroxyapatite biological ceramic has the aperture size and distribution, porosity, hole-through condition and hole surface suitable for growth of bone tissues and is provided with macro pores capable of accommodating grown new bones, and the pore wall of the ceramic is provided with rich lamellar pores, so that the ceramic has an effect of conducting the formed bones. The preparation method comprises the following steps of: setting the orientation, the diameter and the distribution density of macromolecular fibers in a mold in advance, and freezing and solidifying water-based hydroxyapatite slurry by using a directional temperature field, so that the hydroxyapatite powder granules are gathered and rearranged under push rejection of directionally grown ice crystal; and performing freeze drying on the obtained ice blank, sublimating the ice crystal, and sintering, so that fine control of a porous micro structure can be realized. The porous hydroxyapatite prepared by using the method has high hole-through rate and high porosity, and is suitable for growth of the bone tissues.