The present invention relates to radiation cross-linked collagen gel, and a preparation method and usage method thereof. To this end, the present invention comprises a cross-linked collagen material made by irradiating liquid collagen with radioactive rays, wherein the concentration of said collagen is specifically 0.1-10% (W/V), and the radiation dose (dose rate×time) is 0.1-40 kGy on the basis of 1 kGy/hr. The present invention configured as above can prepare a formulated collagen gel using a physical cross-linking method instead of a chemical cross-linking method, specifically carries out the formulation by mixing biocompatible materials, and provides a method capable of using a cross-linked collagen hydrogel in wound dressings, graft materials, cell cultures and the like. Therefore, the present invention provides an industrially convenient and safe preparation method, thereby instilling a good image to a customer by greatly improving the quality and confidence in the products.