The invention discloses a double door casting machine for making the inner liner of a pipeline. The casting machine which comprises an oven with an opening and two clamping devices is characterized in that: each clamping device comprises a support and a rotary disc positioned on the support, and two ends of the pipeline are clamped by the rotary disc and are arranged coaxially with the rotary disc, wherein the support of the first clamping device is provided with a rotary disc driving motor and a feeding tube, the axis part of the rotary disc of the first clamping device is provided with a feeding hole corresponding with the end port of the pipeline, and one end of the feeding tube, which stretches into the feeding hole, is communicated with the inner chamber of the pipeline; and the support of the first clamping device is provided with a baffle door, the opening part of the oven is provided with a vertically elevated door, and the opening of the oven is sealed when the first clamping device and the second clamping device are moved out of the oven. According to the casting machine of invention, the automatic feeding can be realized, and the pipeline can be rotated and dried in the oven; and the heat loss during the pipeline feeding or removing is reduced, and the production efficiency is substantially improved by improving the doors of the oven.