A connection structure for attaching a first electronic device onto a second electronic device is disclosed. The connection structure comprises an action unit and an assist unit, wherein the action unit and the assist unit are particularly designed to be cooperated to each other in case of connecting the first electronic device to the second electronic device. After the first electronic device is attached to the second electronic device through the connection structure, a first electrical connection portion of an electronic card is inserted into an electronic card slot in the first electronic device, and a second electrical connection portion of the electronic card is inserted into an electronic card slot in the second electronic device, thereby making the two electronic devices communicate with to each other through the electronic card. As a result, the function(s) of the first electronic device is expended.