A tail gas exhausting pressure stabilization control system is provided. The system can control the pressure and the flow rate of a gas and a driving gas inputted therein, such that when the gas and the driving gas are mixed and outputted to a tail gas exhausting outlet, the pressure thereof can be controlled under a predetermined pressure. Besides, when the back pressure is generated because of the exhausted gases from the outlet, an energy-saving module can adjust the pressure of the driving gas outputted to an eductor in accordance with the detecting result of the back pressure in order to resist the back pressure. Thus, the exhausted gases from the outlet can be still under the predetermined pressure between the gas and a gas distribution component so as to stabilize the pressure and flow rate of the exhausted gases from the outlet and save the driving gas.