The invention relates to a combined rod completing device of a composite material tower. The combined rod completing device comprises at least one group of rod body components, wherein each rod body component consists of an upper rod body and lower rod body; the upper rod bodies and the lower rod bodies have hollow frustum-shaped structures with openings in the head ends and the tail ends; the cross sections of the head ends of the upper rod bodies and the cross sections of the head ends of the lower rod bodies are smaller than those of the tail ends; the tail ends of the upper rod bodies are sleeved on the head ends of the lower rod bodies; the inner wall surfaces of the tail ends of the upper rod bodies and the outer wall surfaces of the head ends of the lower rod bodies form matched surfaces; adhesives for ingetrally connecting the upper rod bodies and the lower rod bodies are smeared on the matched surfaces; and metal components for enhancing partial rigidity of a rod piece are arranged on the inner walls of the head ends of the lower rod bodies. According to the combined rod completing device, resin is coated on the matched surfaces, so that the upper rod bodies and the lower rod bodies are connected with each other to form a whole; and annular partial enhancement parts formed by solidifying glass fiber yarns or cloth humidified by thermoset resin are coiled on the outer walls of the upper rod bodies, and metal linings are matched with the inner wall surfaces of the lower rod bodies, so that the reliability and the stability of application of embedded composite material rod bodies are effectively guaranteed.