The invention relates to an optical collimator and a manufacturing method thereof. The optical collimator comprises 2N-1 sub-collimators, wherein N is an integer greater than 1. A collimation hole isarranged in a first metal layer to form a first sub-collimator. A collimation hole is arranged in a second metal layer, which is above the first metal layer, to form a third sub-collimator. Between an(i-1)th metal layer and an i-th metal layer, an (i-1)th via layer exists. An (i-1)th via is arranged in the (i-1)th via layer. Then the (i-1)th via is filled by a metal to connect the (i-1)th metal layer and the i-th metal layer. The (i-1)th via layer is a (2i-2)th sub-collimator, wherein i is 2, 3, ..., N; and a collimation hole is arranged in an i-th metal layer, which is above an (i-1)th metallayer, to form a (2i-1)th sub-collimator of (2N-1) sub-collimators. The provided optical collimator and the manufacturing method thereof can improve the optical space filtering performance of the optical collimator.