The present invention relates, in general, to technology applied to entertainment information devices, such as video game machines or computer game programs, information devices for representing geo-spatial information, or information devices for performing three-dimensional rendering using computer graphics and, more particularly, to a protruded displacement mapping method, which represents an object as protruding from a surface. In the image-based protruded displacement mapping method of the present invention, an intersection point search step of searching for an intersection point of a surface of a protruding object, defined by the displacement information, and an observers sight line, and displaying the shape of the protruding object on the polygonal surface, is performed. An overflow representation step of adding a separate polygonal surface and representing a shape of the protruding object, corresponding to overflow deviating from a boundary of the polygonal surface, on the added polygonal surface, is performed. A steeply inclined surface step of detecting a steeply inclined surface in the shape of the protruding object is performed. A steeply inclined surface correction step of representing an additional texture on the steeply inclined surface is performed.