An electrical connector assembly includes a printed circuit board and an electrical connector. The printed circuit board has a circuit board and a soldering board. A plurality of soldering holes is opened on the soldering board. The electrical connector has an insulating housing. A plurality of signal terminals are assembled in the insulating housing and each signal terminal has a soldering tail projecting upward beyond the propping portion for being inserted into the soldering holes and then soldered with the soldering board. A main shell has a lower shell, a front shell for accommodating the insulating housing therein. An upper shell matches with the lower shell to define a receiving room for receiving the circuit board therein. The upper shell has an auxiliary plate covered on the soldering board and cooperating with the front shell to enclose the soldering board thereamong.