An electrical card connector assembly includes an electrical card connector (100) and a PCB (4) where the electrical card connector is assembled. The electrical card connector includes a metal shield (1), an insulating housing (2) and a terminal module (3) received in the insulating housing. The insulating housing associates with the metal shield to define a card receiving room. The metal shield forms a base (10) and a plurality of sidewalls (11) extending from the base. Each sidewall forms a locking portion (111) thereof. Each locking portion has a vertical portion (1110) and a horizontal portion (1111) extending from a lower end of the vertical portion. At least one of the sidewalls forms an elastic piece (12) extending along a card insertion/ejection direction and the elastic piece forms a declined portion (120). The PCB defines a plurality of cutouts (44) and at least one aperture (47). The elastic piece is locked with the aperture under a guiding force of the declined portion while the horizontal portions of the locking portions pass through the cutouts and then confront the bottom surface of the PCB.