A method of computing CGH using look-up table and temporal redundancy and an apparatus thereof are disclosed. The apparatus includes an extracting unit, which extracts a brightness image and a depth image from a target frame of 3D video, a comparing unit, which extracts a change point that is different from a point of the target frame after comparing the brightness image and the depth image of the target frame to a brightness image and a depth image of a previous frame, a hologram computing unit, which computes hologram information by differentiating hologram computing methods using hologram patterns depending on whether a ratio between the number of the change points and the number of the entire frame points is equal to or greater than a predetermined critical value, and a storing unit, which stores the brightness image and the depth image of the target image and the hologram information.