The invention discloses a built-in spring type tapered jack structure. The built-in spring type tapered jack structure comprises a jack body and a tapered jack sleeve, wherein the jack body is provided with a jack sleeve telescopic cavity, the tapered jack sleeve is telescopically and movably arranged in the jack sleeve telescopic cavity, a spring is connected between the bottom of the jack sleeve telescopic cavity and an end part of the taper jack sleeve, contact spring sheets are arranged on side walls in the jack sleeve telescopic cavity of the jack body and are correspondingly in electrical contact with the outer side part of the tapered jack sleeve, a plugging cavity is formed in the tapered jack sleeve, and a limitation device is arranged at an opening part of the jack sleeve telescopic cavity of the jack body and is used for limiting a socket part of the plugging cavity. The built-in spring type tapered jack structure is arranged between two fixed plates, the spring is arranged inside the jack body, and current transmission between the jack body and the tapered jack sleeve is ensured by employing the contact spring sheets; and when the jack body is inserted into the tapered jack sleeve, each single tapered jack sleeve moves relative to the jack body under the effect of pins, the jack body and the fixed plates cannot integrally move and cannot be clamped, and favorable contact is achieved.