The invention discloses a thermoplastic plastic lining steel tube hohlraum internal permeation gas detection control system in the technical field of gas permeation performance testing. Two pipe systems of the same structure are symmetrically arranged at the two ends of a steel tube flange, each pipe system comprises a steel tube and a thermoplastic plastic lining tube attached to the inner wall of the steel tube, a flowback pipe is arranged at the top of each pipe system, a pressure meter is arranged at the top of the flowback pipe on the left side through a first exhaust value, a sensor setis arranged at the top of the flowback pipe on the right side through a second exhaust value, and a wireless data transmitter is arranged at the top of the sensor set; and the two flowback pipes are communicated through a connecting transverse pipe, and a gas gathering pipe is connected to the top of the connecting transverse pipe through a sealing piece. By means of the device, it is guaranteedthat hohlraum permeation gas enters a running pipe again, natural gas waste is avoided, free discharge of poisonous gas like H2S is avoided, and personnel harms and environmental pollution risks are reduced.