A microlens array and a method for fabricating thereof are provided. The microlens array of the present invention comprises a lens structure part formed by bistable dielectric polymer thin film; first and second electrode parts each formed on the upper surface and the bottom surface of the lens structure part to apply voltage for shape changes of the lens structure part; a circuit part applying heat to the dielectric polymer thin film to change the property of the dielectric polymer thin film to be soft; and a base part formed on the bottom surface of the second electrode in predetermined intervals. The method further comprises a hydraulic part to apply predetermined voltage to the bottom surface of the lens structure part. The microlens array is thus able to change optical properties by deform the shape of a transparent dielectric polymer thin film having bistablity to various sizes of lens shapes by the purposes.