In in-vitro culture, we have found that corneal endothelial cells exhibited membranous growth character in tissue culture. The cells were polygonal in shape. When human corneal endothelium grew in single layer, we found the phenomenon of amitosis. Scanning electronmicroscopy showed the microvilli of endothelial cells in vitro were more than in vivo. Transmission electronmicroscopy demonstrated a lot of intercellular desmosome and many fibrillar structures accumulated into bundles, curly-hair-like in shape and distributed reticularly around the nucleus. The cells were rich in organelles. We have also discussed the regenerative ability and some biological characteristics of corneal endothelium. It may be suggested that human corneal endothelia exhibit the proliferative ability in some condition. However, their proliferative form remains to be further studied.