Abstract: The material selection of high-pressure natural gas vent pipeline was studied. The operating temperature of natural gas vent pipe is low, which exceeds the avowable lower limit temperature of ordinary carbon steel. In this case, low temperature and stress conditions should be considered. By calculating the operation temperature, operation pressure and stress of a natural gas vent pipe, whether it is in the condition of low temperature and low stress is analyzed. The results show that when the vent pipe operating pressure is below 1.0 MPa for normal operation, the axial tensile stress is below 10% of the minimum tensile strength value of steel 20^#. Pipeline operation condition is "low temperature and stress condition". Therefore, 20^# steel can be used as natural gas vent pipe.