A system for rendering 6 degree-of-freedom virtual reality according to an embodiment of the present disclosure includes a visibility test module performing a visibility test for determining whether a current point of interest where a main viewpoint is directed is visible for each of a plurality of reference viewpoints and generating visibility information by identifying the number of invisible fragments of each reference viewpoint according to the performance result, a reference viewpoint selection module selecting a final reference viewpoint for a rendering process for a current frame based on the visibility information for each of the plurality of reference viewpoints and a preset selection criterion, and a rendering process module performing an image-based rendering process by using a color image and a depth image corresponding to the final reference viewpoint.