Present embodiments provide for an ocular optical system. The ocular optical system includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element positioned in an order from an eye-side to an display-side. Through designing parameters satisfying at least two inequalities and convex and/or concave surface of lens elements, the improved ocular optical system may provide better optical characteristics, a decreased effective focal length and an enlarged angle of view while the total length of the ocular optical system may be shortened.