The invention relates to an adapter connector and a signal transmission module thereof. The signal transmission module comprises an internal signal conductor, an external shielding ring sleeve and aninsulator between the signal conductor and the shielding ring sleeve, and insulation tongues extended to the outer portion of the shielding ring sleeve are integrally formed at two ends of the insulator or fixedly arranged in two parts. The signal conductor comprises a main body portion arranged in the insulator and insertion terminals fixedly arranged on the insulation tongues, the insulation tongues are provided with shielding pieces communicating with the shielding ring sleeve, and the insulation tongues, the insertion terminal and the shielding pieces commonly form an insertion head. The external portion of the main body portion is provided with the insulator, and the outermost portion of the main body portion is provided with the shielding ring sleeve to achieve fully enclosed shielding of signal conductor electromagnetism, when the scheme is concretely applied to the adapter connector, the mutual interference between signal conductors is avoided. The insertion head comprises theinsulation tongues, and the shielding pieces and the insertion terminal are located on the insulation tongues to enhance the whole strength.