The invention discloses a combined connector structure of a steel pipe, an auxiliary tool and a manufacturing method in order to solve the problem that the anti-corrosion effect of on-site welded joints of conventional inner anti-corrosion carbon steel pipes is poor. The combined connector structure includes a long-segment thin-wall stainless steel pipe and a short-segment thick-wall stainless steel pipe; the long-segment thin-wall stainless steel pipe is used as a lining in a thick-wall carbon steel pipe to achieve the purpose that the long-segment thin-wall stainless steel pipe and the thick-wall carbon steel pipe are both in friction welded connection with the short-segment thick-wall stainless steel pipe; the auxiliary tool includes a push-pull rod, a baffle ring, a jacking screw, an elastic rack, a pipe clamping head, a rotating ring, screws, check rings, an insulating drum, a grinding wheel, a gasket and a nut and is used for clamping and supporting the long-segment thin-wall stainless steel pipe during friction welded connection and polishing and machining the trimming of the inner wall of a welded joint after welding. Not only can the cost of existing inner anti-corrosion carbon steel pipes serving as the raw materials of connectors of stainless steel pipes be reduced, but also the difficulty of an on-site welding process is not increased, and meanwhile the anti-corrosion effect of a pipeline after on-site welding construction can also be ensured.