An electrical connector assembly comprising a base defining a plurality of passageways and a conjugate member, a plurality of terminals residing in corresponding passageways, and a pick up cap being detachably mounted on the base and defining a conjugate post. The conjugate member having a hole and the conjugate post having a plurality of interferential robs for abutting against the interior wall surface of the conjugate hole. With this configuration, there is a reserved space to hold the plastic scrap produced by the conjugate post and the conjugate hole when the electrical connector is mating with the pick up cap, so that the pick up cap can be easily mounted on the electrical connector.