An electrical connector includes an insulative housing, a plurality of terminals retained in the insulative housing. The insulative housing has a receiving room and a mating part received in the receiving room, the mating part defines a mating hole and a pair of receiving grooves extending rearward on two lateral sides of the mating hole. The terminals include a detecting terminal received in the mating hole and a pair of power terminals received in the receiving grooves. The mating part further defines a pair of guiding surfaces on two sides of the mating hole and a pair of stiffening ribs on two sides of the receiving groove, which can reduce the mating force during the mating process and protect the mating part.