Corneal endothelium controls the hydration and thickness of corneas, .thus controls the transpanrency of corneas. So any method of cornea preservation must ensures that endothelium has high viability and high percentage of entact.endothelial cells. In the past several decades, with the development of methods of cornea preservation, emphasis has been given to the methods of assessment of corneal viability, and many methods, had been founded and used, such as the simple and useful method of combined staining. Brief introduction and comment are given in this paper.