An electrical connector assembly (100) in accordance with a preferred embodiment of the present invention, comprises an electrical connector (200) for connecting an electronic package with a circuit substrate (60) and a connecting device (300) for fixing the electrical connector (200) to the circuit substrate (60). The electrical connector (200) includes a housing assembly (1) with a plurality of contacts (10) received therein. The connecting device (1) includes a first screw (70), a second screw (90) and a nut (80) connecting the first screw (70) and the second screw (90). The nut (80) connecting with the first screw (70) makes the first screw (70) securely located on the housing assembly (1) and prevents the first screw (70) losing in the transportation.