The molecular basis of schnyder crystalline corneal dystrophy(SCCD)is UBIAD1 gene mutation. The pathogenesis of SCCD includes conformational change of UBIAD1 protein which leads to loss of combination with GGpp compounds. UBIAD1-HMG CoA reductase complexes can't be separated, and the rate-limiting enzyme can't dissociate from endoplasmic reticulum to cytoplasm, which results in loss of recognition and degradation by the proteasome. The direct consequence is the gradual accumulation and biosynthesis of cholesterol and non-sterol isoprenoids compounds in the cell. This paper reviews the clinical manifestation, molecular basis, pathogenesis of SCCD and the function of UBIAD1 which provide guidance for molecular diagnosis and treatment of SCCD and pave the way for elucidating the function of UBIAD1 in vivo.