An electrical connector assembly (100), comprises: a housing (1) having an upper shield part and a lower shield part (16) assembled with each other, and the upper shield part having at least two shield covers (15) arranged side by side along a transversal direction; a plurality of retaining pieces (9) assembled to each of two adjacent shield covers and interconnecting with the two adjacent shield covers; a plurality of printed circuit boards (2) disposed in the housing; a latch mechanism assembled to an exterior surface of the housing; and a metallic holder (8) surrounding and engaged with the housing.