The utility model relates to a bi-metal composite pipe with end parts being with external threads. A lining pipe is composited in a matrix pipe; adapter rings are welded on the two ends of the matrix pipe and the lining pipe; a circle of weld joint is formed between one external ends of the matrix pipe and the lining pipe and each adapter ring; and pipe threads are processed on the external surfaces of the end parts of the matrix pipe and the external surfaces of the adapter rings. When two bi-metal composite pipes are connected through the pipe threads by a coupling, corrosion medium cannot be in contact with the end parts of the matrix pipe so as not to enter into the matrix pipe to corrode the matrix pipe from a clearance between the matrix pipe and the lining pipe, so that the matrix pipe cannot be corroded, electrochemical corrosion caused by potential difference between the ends of the matrix pipe and lining layer materials is avoided, and the corrosion resistance of the composite pipe is ensured. According to the bi-metal composite pipe with the structure, the technical problem that the threads of the composite pipe all adopt corrosion-resisting alloy so as to be easy to glue is avoided, the technical problem of thread connection of the bi-metal composite pipe is fundamentally solved, and the bi-metal composite pipe can be popularized and used in technical fields such as petroleum and chemical industry.