The invention provides a telescopic gas supply pipeline for a slender combustion chamber, and belongs to the technical field of aerospace propulsion power systems. The telescopic gas supply pipeline for the slender combustion chamber comprises an outermost pipeline, an innermost pipeline, a middle pipeline, a pipeline sealing ring, a guide rod, a guide structure, a driving device and a fixing device. The driving device comprises a frequency modulation motor, a motor base and a gear. The fixing device comprises a bearing end cover, a cylindrical roller bearing, a flange plate, a fixing rod, a sleeve, a bearing end cover sealing ring and a supporting rod. The pipeline can be controlled in a single side, the continuous extension and shortening of the pipeline are achieved in a limited space,the stretching at different speeds and rapid stopping switching can be achieved, and the function switching is rapid. Through screw thread transmission of a screw rod, the telescopic supply is accurate and reliable, and the pipeline has good sealing performance and is suitable for operation and use in a high-pressure environment. The telescopic gas supply pipeline for the slender combustion chamber of the invention is simple in structure, stable in operation and convenient to maintain, and can be simply modified to be suitable for working environments with different depths, lengths and spaces.