The first bullet train left Beijing on Wednesday morning. Trains will initially travel at 300 km/h (187 mph), more than halving travel time.
A Chinese official has described the route – parts of which were already in operation – as “one of the most technically advanced in the world”.
The 2,298 km route will have 35 stops.
They include such major cities as Wuhan and Changsha.
The previously 22-hour journey will now take less than 10 hours.
The decision was taken to start the passenger service on 26 December to commemorate the birth of former Chinese leader Mao Zedong, state media said.
China is currently expanding its high-speed rail network across the vast country.
But the ambitious project has not been free from controversy.
Forty people died last summer in a crash on a rapid train line in eastern Zhejiang province and the entire high-speed scheme has been dogged with reports of corruption.
03_3cBou9dgImage source: Wikimedia Commons President-elect Donald Trump celebrated his election victory at the Ultimate Fighting…
Millions of voters across the US chose to return Donald Trump to the White House…
Donald Trump declares victory in the US election as he addresses jubilant supporters in Florida.…
Stocks around the world are rising as Donald Trump appears to be on the cusp…
Donald Trump has won Pennsylvania, North Carolina and Georgia and taken a lead over Kamala…
Quincy Jones, the celebrated musician and producer who worked with Michael Jackson, Frank Sinatra, Ray…