The invention belongs to the field of biological patches, and relates to a dural biological patch and a preparation method thereof. The raw material of the dural biological patch of the invention is not from commercial meat animals, but from breeding animals, such as a multiparous sow SIS patch, which has natural and good mechanical properties; plant-derived reagents are adopted in the decellularization link in the method of the invention, using such natural mild reagents has no damage to ECM natural structural base, can retain more effective active ingredients, and has better ability of inducing tissue repair and growth; and the method of the invention neither uses a crosslinking agent to enhance the mechanical properties, nor uses a synthetic detergent for decellularization, so as to avoid the residue of chemical reagents and the toxicity of the residue, and retain more active components in the ECM at the same time, especially the content of GAGs. According to the present invention,the dural biological patch not only has soft texture and good toughness, is easy to suture tightly, and can prevent cerebrospinal fluid leakage, but also has the characteristics that the degradation speed is basically synchronous with the growth of new dura, and is more conducive to the repair and regeneration of the dura.