The present invention discloses a foldable base with a main body comprising a long groove, a latching section, a latched section and an insert slot; wherein the main body can be folded along the long groove to connect the latching section with the latched section to define a three-dimensional shape or unfolded to separate the latching section and the latched section and then spread the main body open along the long groove to define a sheet. The insert slot is coupled to a fixed base being coupled to a main system such as a personal computer (PC) or a personal digital assistant (PDA) by a transmission line, enabling a user to insert an electronic device such as a flash drive or a MP3 player through the insert slot into the fixed base.