An insulated electrical connector formed by one-time injection molding is disclosed. A base of each metal female terminal has two edges extending upward and inclining relative to each other to form elastic clamping pieces, and an edge extending outwards to form a weld leg. An insulated rubber core is formed on the metal female terminals by one-time injection molding. The bases are embedded in the insulated rubber core. The elastic clamping pieces are received in cavities of the insulated rubber core. Insertion holes corresponding to the elastic clamping pieces are formed in bottoms of the cavities. Conical guide-in faces are formed at bottoms of the insertion holes. The weld legs stretch out of the insulated rubber core. The insulated electrical connector is convenient to install and realizes stable electric connection.