An electrical connector secured to a PCB having a plurality of welding areas on an upward face and a plurality of through holes running through the PCB includes an elongate insulative housing and a plurality of contacts assembled to the insulative housing. The insulative housing defines a mating face and a mounting face opposite to the mating face, a plurality of blocks protruding from the mounting face. Each contact defines a contacting portion connecting with a mating connector, a retaining portion retained in the insulative housing and a soldering portion welding to the welding areas of the PCB. A plurality of board-lock pieces made of metal material are under the corresponding blocks to clip the PCB between the blocks and the board-lock pieces. A projection from one of the board-lock piece and the block is inserted into the through hole.