The present invention provides an acellular collagenous tissue and a method for processing an artificial heart valve containing the acellular collagenous tissue. The method comprises immersing the acellular collagenous tissue in a preservation liquid containing an ionic liquid until the size of the acellular collagenous tissue remains stable in a non-liquid environment. The present invention also provides a preservation method, comprising immersing the acellular collagenous tissue or the artificial heart valve containing acellular collagenous tissue in the preservation liquid containing ionic liquid until the size of the collagen tissue remains stable in the non-liquid environment, and after taking out the acellular collagenous tissue or the artificial heart valve containing the acellular collagenous tissue, removing the excessive preservation liquid adhered to a surface thereof , and packaging the acellular collagenous tissue or the artificial heart valve. The present invention also provides an acellular collagenous tissue and an artificial heart valve containing the acellular collagenous tissue processed by the method described above. The method provided by the present invention can effectively avoid a biological material damage caused by being in a non-liquid environment and is beneficial to implement a subsequent processing and sterilization for the biological material.