A process for fabricating a micro-optical lens comprises forming a wall post structure on a substrate, coating with a polymeric film on the wall post, then making it adhering over both sides of the wall post structure by a transverse etching on the substrate around the base of posts. After an isolating process and a proper heating treatment, said polymeric film cohering to form a plano-convex lens. By controlling the respective amount of the polymeric film on both sides of said wall post structure, the polymeric film can combine with the wall post structure to form a composite material biconvex micro-lens, plano-convex micro-lens and the like. Alternatively, a single material micro-lens can be formed by imaging the profile of the polymeric micro-lens on the wall post structure via an etching process.