The invention relates to a water-sweeping, 
drying and inerting integrated process for a 
natural gas transportation pipeline. The water-sweeping, 
drying and inerting integrated process for the 
natural gas transportation pipeline comprises the following steps: putting a pipeline cleaner 
train into the 
natural gas transportation pipeline by virtue of a pipeline head-end ball launching 
barrel, wherein the pipeline cleaner 
train consists of a pipeline cleaner I, a freshwater section plug, a pipeline cleaner II, a water-based gel section plug, a pipeline cleaner III, a chemical 
drying agent section plug, a pipeline cleaner IV, a 
dry gas section plug and a pipeline cleaner V; injecting compressed and dried 
nitrogen gas into the natural gas transportation pipeline from a gas inlet pipeline to push the pipeline cleaner 
train to travel forwards in the natural gas transportation pipeline, and exhausting pressure test water from a pipeline 
tail-end ball receiving 
barrel and a water exhausting pipeline; and after the pipeline cleaner train reaches the pipeline 
tail end, sequentially taking out the pipeline cleaners from the pipeline 
tail-end ball receiving 
barrel, and exhausting freshwater, water-based gel, a chemical drying agent and 
dry gas from a water drainage pipeline. After passing balls once, the water-sweeping, drying and inerting integrated process can reach conditions of introducing natural gas and putting the introduced natural gas into production.