An Express Card adapter card structured from a plastic frame, a connector and two metal covers, and characterized, in that front and rear ends of the plastic frame are provided with an Express Card insertion opening and a placement area for installing a connector respectively. Two side outer edges of each of the metal covers are respectively provided with inwardly bent hook strips, which enable hooking within the corresponding grooves. Internal edges of each of the metal covers are provided with a plurality of catch hooks, a grounding elastic strip and a hook portion. According to the aforementioned structure, it is not only convenient and economical to manufacture, moreover, after rigid fixing, the firm structure assures the Express Card adapter card will not easily come apart.