Abstract: Gas pipelines are commonly dried by means of pigs and dry air, but both methods cannot guarantee the drying effect, resulting in the risk that hydrate and ice blockage may be generated after the pipeline is put into production and boosted. In this paper, the rationality of water dew point acceptance index of gas pipeline drying operation was studied to verify the drying effect during the construction of gas pipeline. According to the PR equation, the transformation relationship between water dew point and water content of gas mixture was obtained and the calculation software was worked out. Then, a certain gas pipeline was taken as an example to provide the calculation process of water dew point index for drying acceptance. And it was pointed out that the defect of water dew point control indexes in Technical Specifications for Drying Operation of Gas Pipeline is that the effect of pressure on water dew point is not considered. Finally, references of water dew point acceptance index of gas pipeline drying under different pressures were provided based on the design parameters of pipeline process, so as to guarantee the drying effect of gas pipeline after it is put into operation.