A piercing electrical connector includes a wire end connector. The wire end connector has a wire end body, a wire end terminal, and a wire cover engaged with the wire end body. The wire cover has a wire holding hole, and the wire end terminal has a piercing portion. The wire cover further has a clasping plate, a clasping arm and a first clasping head. The wire end body has a clasping groove, a clasping hole, a protrusion located in the clasping groove, a pre-locking groove and a locking groove that communicate with the clasping hole. When the wire end connector needs to be transported, the first clasping head extends into the pre-locking groove, and the protrusion abuts against a free end of the clasping plate so that the wire cover and the wire end body are pre-assembled together, and the piercing portion does not pierce a cable wire.