A double-sided microlens array is applied to a laser beam shaping and homogenizing device of a laser system. The double-sided microlens array is able to shape the energy distribution of an incident laser beam to a square and flat-top beam with the average uniformity of energy and comprises a base plate, a plurality of first micro lenslets and a plurality of second micro lenslets. The first micro lenslet and the second micro lenslet have the convexes with the same figures and comply with the classification of an optical diffractive element, the first micro lenslets and the second micro lenslets are disposed on the first surface and the second surface of the base plate, which are corresponding to each other in order to tightly line up the arrangements of arrays. The first micro lenslets and the second micro lenslets are correspondingly misalignment.