The 4.0 to 5.2-billion-dollar pipeline will transport 12 billion cubic metres (420 billion cubic feet) annually from the Tarim Basin in western Xinjiang region to the Yangtze Delta region in the east, the China Daily reported.
The construction of the trunk line was completed earlier this month and will see gas flow beginning Wednesday. It will be available for customer distribution five days later, the newspaper said.
China's largest oil and gas company, PetroChina, is the sole operator of the pipeline after a consortium of foreign partners led by Royal Dutch Shell failed to strike a deal following two years of negotiations.
The breakdown in the initial agreement means PetroChina is financing the project itself and has been studying the possibility of a domestic listing to do so, the company has said.
This may entail raising a reported 3.6 to 4.0 billion dollars in what would be the country's largest ever share offer.
The pipeline itself, which is central to China's energy policy shift away from reliance on coal to cleaner burning gas, is intended to supply up to 10 percent of the country's fuel consumption by 2020.
China is trying to increase its access to natural gas reserves as part of efforts to shore up its energy supplies and reduce its heavy reliance on coal, which currently accounts for about 70 percent of its energy consumption.