The plane, which aims to compete with the Airbus 320 and Boeing 737 globally, is ready for ground tests and is expected to make its maiden flight next year.
It took seven years for it to progress from the project launch stage to the rollout.
Vice-Premier Ma Kai said at the rollout ceremony, "The research and development of a big passenger aircraft is a complex systematic engineering project, and the rollout is an important milestone for this project."
Ma said the C919 has entered a key stage in preparing for its maiden flight, and the manufacturer also faces tough tasks ahead.
Jin Zhuanglong, chairman of Commercial Aircraft Corp of China, which built the C919, said the maiden flight is scheduled for next year. Before this, the aircraft will soon face a wide range of tests, Jin said.
Li Jiaxiang, head of the Civil Aviation Administration of China, said the domestic civil aviation industry had been calling for a domestically developed aircraft to be put into operation as soon as possible.
Li said 2,635 transport air-craft had been registered with the administration so far this year, but only 23 were domestically manufactured.
"There is an urgent need to make China strong in civil aviation," Li added.
The C919 has received 517 orders from 21 clients globally, including leading domestic carriers and leasing companies.
Minister of Industry and Information Technology Miao Wei said the aircraft's rollout marks a solid step in thoroughly implementing the "Made in China 2025" strategy and accelerating the nation's progress to becoming a strong manufacturer.
"The next 15 to 20 years will be an important period in opportunities for the development of China's civil aviation industry," Miao said.
The implementation of the Belt and Road Initiative provides more scope for China's aviation industry to deepen international cooperation and achieve mutual benefits and "win-win results", he said.
Sixteen joint ventures have been set up between Commercial Aircraft Corp of China's foreign suppliers and Chinese aviation manufacturers nationwide.
More than 100,000 people from 200-plus companies in 22 Chinese provinces have participated in the C919 project to date.
The short-to-medium-range single-aisle jet can seat between 158 and 174 passengers and has a standard range of 4,075 kilometers.
Apart from the basic version of the plane, the manufacturer will also launch extended, shortened and cargo versions of the C919 along with a business jet in the future.
With manufacturing capacity comparable to global standards, the corporation's assembly and manufacturing center in Shanghai's Pudong district has set up five assembly lines for the C919.
The corporation's assembly and manufacturing center in Shanghai's Pudong district has set up five assembly lines for the C919.