Corneal collagen cross-linking(CXL) is a new treatment for keratoconus. Based on the topical administration of riboflavin and irradiation with ultraviolet A (UVA) light of 370nm, this procedure can lead to photosensitive reaction and thus to induce cross-linking between and within collagen fibrils in order to increase rigidity and biomechanical stability of the cornea. This new approach has been also shown to be an effective treatment for some kinds of other corneal diseases. However, recently, adverse effects and complications related to epithelial removal have been reported. For this reason, researchers proposed the transepithelial corneal collagen cross-linking. The purpose of this paper is to review the basic principle, procedure, effect of epithelial removal and the laboratory and clinical researches about transepithelial corneal collagen cross-linking with Riboflavin/UVA.