Posterior lentiglobus is an uncommon abnormality in the shape of the crystalline lens, characterized by a progressive spheroidal protuberance affecting the posterior lens surface. We reported a case of posterior lentiglobus with cataract successfully treated by lens aspiration and intraocular lens (IOL) implantation. Transmission electron microscopy of the posterior lens capsule revealed the thinnest diameter is only 1.83 mm. We found no typical thinned basal lamina with basement membrane disruptions and unusual nodular structure. Maybe the thinning posterior lens capsule in the central part comes from the pressure of bulging lens.