An automatic disk feeding device for a disk duplication device and method thereof which comprises two transport assemblies (2) disposed at both sides of a disc holder (1). Each transport assembly (2) comprises a linkage disk (20) which drives a connecting rod (30) to rotate, and then the connecting rod (30) moves a sliding block (50) which cooperates with a push member (60) and a slide rail (70) to slide to and fro. The sliding block (50) is defined with slant pushing grooves (52), and the slide rail (70) is defined with L-shaped tracks (71). The push member (60) is provided with pushing protrusions (61) and guiding protrusions (62) inserted in the pushing grooves (61) and the L-shaped tracks (71). Thereby, the push members (60) can clamp the disc by a horizontal extending method firstly, and then lift the disc, thus automatically taking out the disc in a small space.