An asymmetric curved-surface prismatic image display optical system includes a first prism and second and third prisms respectively arranged in front of and behind the first prism. The first prism includes a light-exiting planar surface that is at an eye-adjacent side and is opposite to a light-entering planar surface of the second prism with an air gap therebetween and may serve as a reference for inspection of a free-form curved surface. The second prism has a light-exiting planar surface at the eye-adjacent side and parallel to a side planar surface of the third prism to allow an external-world image to be seen more clearly. Light from an image displaying panel first enters the first prism and is subjected to total internal reflection by the light-exiting planar surface toward the reflective curved surface to be reflected and re-directed to transmit through the second prism for image formation on a retina.