The invention discloses a tail connection assembly with a built-in optical fiber cable, and a connection method. The assembly comprises a cable which comprises an outer sheath, a conductor, and an optical fiber which is disposed in the conductor; and a wiring terminal which comprises a cup joint part and a wiring part which is disposed at one end of the cup joint part. An end face, far from the wiring part, of the cup joint part is provided with a cup joint hole, and the cup joint hole is used for the fixed cup joint with an exposed end of the conductor. A bottom wall surface of the cup jointhole is provided with a leading-out hole which is disposed in the depth direction of the cup joint hole, and the leading-out hole is used for the leading-out of the optical fiber. According to the invention, the wiring terminal is in fixed cup joint with the cable conductor, and the optical fiber is led out of the leading-out hole which extends in the depth direction of the cup joint hole, and isnot liable to be compressed, so the leading-out is safe and reliable.