An electrical connector assembly for electrically connecting an electrical package to a printed circular board, includes an electrical connector mounted on a printed circular board, and a heat dissipating device located upon the electrical package. The heat dissipating device includes a supporting body located upon the electrical connector, two latching pieces retaining the supporting body and heat pipes assembled on the supporting body. The latching piece rivets with the supporting body on a center part thereof, so when one end of the latching pieces is pressed downwardly, the opposite end will not be influenced.