The invention discloses bamboo joint type composite frame pipe fittings and a forming method. In the pipe fittings, a fiber cloth material preformed composite section is rolled, an air bag is arranged in the whole cavity of the composite section, and a nozzle is arranged on the air bag; two ends of the composite section are rolled into carbon fiber reinforcing ribs; two cavity walls of the composite section extend outwards to preform a pipe fitting; an air pipe and a nozzle are respectively arranged on two ends of the pipe fitting; the pipe fitting is heated, and air is inflated into the inner cavity of the pipe fitting through the nozzle; the reinforcing ribs in the pipe fitting and the pipe fitting are integrally hardened and formed; the air bag is taken out to form two sections of reinforced bicycle pipe fittings; because air pressure at two sides of the reinforcing ribs is balanced and positioned, the pipe fitting can be formed into an upper pipe, a lower pipe and a vertical pipe and assembled into the frame; and two sides of the reinforcing ribs in the pipe are balanced and positioned by the air pressure in the forming process, so that the reinforcing ribs of the formed frame pipe fitting are prevented from displacement to achieve the aim of improving rigidness of the pipe fitting.