Provided are a plug and an electrical connector component. The plug includes an insulating body, a circuit board fixed to the insulating body, and a cable electrically connected with the circuit board and extending backwards from the insulating body. The insulating body includes a body part and a mating part which extends forwards from the body part; the circuit board has an inserting part that protrudes forwards out of the mating part; metal contact pieces are distributed on upper and lower surfaces of the inserting part; the insulating body is provided with a pair of baffle plates extending forwards from the body part; a pair of the baffle plates are respectively arranged on left and right sides of the mating part; and a limiting groove configured to guide the insertion of the plug with the socket is formed between each of the baffle plates and the mating part.