Disclosed herein are an imaging processing apparatus for representing an object realistically, and an imaging processing method thereof. The image processing apparatus includes: a volume data generator configured to generate volume data of an object; a volume renderer configured to project the volume data to a first plane with respect to a user's viewpoint, and to acquire a projection image, wherein the volume renderer determines a value of each pixel of the projection image based on respective distances between first surface points and second surface points, the first surface points being points that are shown from the user's viewpoint from among points constituting a surface of the volume data, the second surface points being points that are shown from a position of virtual light from among the points constituting the surface of the volume data.