A pipe-fitting wiring assembly for a brake cable and a shift cable on a bicycle comprises a stopper which is fixed at a pipe fitting wiring hole on the bicycle in an inlaid manner, wherein the stopper comprises a brake cable through hole used for passing of the brake cable as well as a shift cable through hole used for passing of the shift cable. The assembly also comprises a stopper plug which is inserted and fixed in the brake cable through hole and used to clamp a shell of the brake cable. The shift cable through hole is a stepped hole and can support a shell pipe opening of the shift cable on an upper ring face of the stepped hole; the stopper plug comprises an opened fixation hole used to clamp and fixe the brake cable shell; the stopper plug also comprises a fixation ring which can pass through the shift cable through hole; and the stopper also comprises a wire pipe end sleeve which can be inserted into the stepped hole and can limit the shift cable shell pipe opening at the stepped hole after sleeving of the wire pipe end sleeve. According to the invention, the brake cable and the shift cable can pass through a pipe at the same time, so in-pipe wiring can be achieved; and only the inner shift cable is retained in the pipe, so friction of the shift cable can be reduced.