In order to realize the high performance detection of CO₂ gas isotope, a multi-pass gas cell temperature and pressure control system with high precision and stability was developed in this paper. Flexible PCB was used as heating sheet to cover the cylindrical multi-pass cell. Considering the heating rate of the temperature control system, the outer coating of thermal insulation cotton served as the heat insulation device, which enabled the whole temperature control system to achieve rapid heating and keep the temperature stable for a long time. Platinum resistance PT1000 temperature sensor was utilized to accurately collect the multi-pass gas cell temperature. The main controller regulated the heating power of the flexible PCB heating film through PWM signal, so as to realize the closed loop of temperature control. In terms of pressure control system, the pressure sensor was connected to the front and back end of the multi-pass gas cell to measure the inside pressure of multi-pass gas cell. The main controller regulated the proportional valves that were at the front and back end of the multi-pass gas cell via PWM signal, so as to realize the closed loop of pressure control. The results show that the temperature control range is from 18.48 ℃ to 42 ℃, and the temperature control precision is ±0.08 ℃. When the pressure of the multi-pass gas cell is 60 Torr (1 Torr ≈ 133.322 Pa), the control accuracy is ±0.04 Torr. The system provides reliable guarantee for the high performance measurement of infrared CO₂ gas isotope.