Abstract: The present invention discloses a memory card adapter structure, comprising a main body and a baseboard. The main body is overlapped on the baseboard and has a socket on one end. The socket can host different types of memory cards. There are multi PIN receptacles in the socket. On the baseboard, there is a containing hole against the PIN receptacles on the main body. Furthermore, there is a connector at one side of the baseboard. When the main body is coupled with the baseboard, the PIN receptacles will enter into the containing hole, and then the PINs in the receptacle will contact with the baseboard to form a closed circuit. In this way, different memory cards can be connected to the adapter to transfer signals and data at different times.