A system and method for supporting augmented reality in an ocean scene is provided. According to the system and method, camera rotation information is extracted from horizontal line information of a sea extracted from an original image including a focal length and at least two first natural feature point tracking data existing on a sea plane and a plane parallel to the sea plane, using long-distance background features; camera movement is sequentially calculated from the camera rotation information and at least two natural feature point tracking data existing on the sea plane of the original image; and a computer graphics object is placed on a ground plane by importing camera position data, and a rendering is performed as moving the camera. Accordingly, the camera rotation and the camera movement can be accurately calculated, assuming that the camera focal length information is known at the time of capturing a moving image with a sea image for a background, and thus the CG/real scene synthesis with the sea for a background can be accomplished more realistically and accurately during the production of videos such as movie and drama.