An electrical connector includes an insulative housing, a plurality of contacts, and a fastener. The insulative housing has a plurality of contact-receiving passageways and a positioning slot recessed upwards from a bottom face thereof, the positioning slot is communicated with the contact-receiving passageways. The fastener is assembled into the positioning slot before the contacts being inserted into the insulative housing. Each contact defines a stopping portion and an elastic locking arm, the locking arm extends backwards to form a free end, and the free ends of the locking arms are locking with the insulative housing to realize a pre-position between the contacts and the housing, after the contacts assembled into the insulative housing, the fastener is pressed upwards into the positioning slot fully and abutting against a rear end of the stopping portion to form a secondary positioning.