Abstract: The paper analyzes the problems existed during the gas purging in Jingbian-Shanghai Gas Pipeline of West-to-East Gas Pipeline Project, including the selection of purging sequence, determination of with/with-out-pig plan, determination of nitrogen injection point, nitrogen injection temperature and volume and selection of gas flowing velocity. The analytical results show that it is feasible that the gas purging sequence should be the trunkline first and then the branch line, plus stations without pigs at the purging velocity of 5 m/s based on the nitrogen injection calculations. For the problems in gas purging, the authors put forward instructive suggestions.