The invention relates to a porous scaffold for cartilage tissue engineering and a preparation method thereof, belonging to the technical field of biomedical materials. Specifically, it is a three-dimensional porous scaffold composed of carrageenan and chitosan, with a porosity of 80-96% and a pore diameter of 50-500 μm; its preparation method is to prepare a carrageenan solution with distilled water, prepare a chitosan solution with a dilute acid solution, and mix it with After beating separately, blending, stirring, adding sodium carbonate crystal powder, beating again, pouring into a stainless steel mold in a water bath, freeze-drying, then immersing in a dilute acid solution, soaking in distilled water, and finally vacuum-drying to obtain cartilage tissue engineering Porous scaffold. The raw materials selected by the invention have a wide range of sources and are safe, and the product has certain functionality, high hardness, high porosity and no harmful residue, and is more suitable for tissue cell culture or cartilage tissue regeneration; the preparation method is simple and easy, and the industrialization prospect is broad.