The MTR Corporation, which operates Hong Kong metro, will run one of the UK's largest rail franchises, the Department for Transport announced on Monday (27 March).
Hong Kong Exchange-listed MTR and First Group will take over from Stagecoach to run South West Trains for seven years from 20 August.
The UK government said passengers can look forward to more space and faster rail services.
"First MTR South Western Trains Limited will deliver the improvements that people tell us they want right across the South Western franchise area, from Bristol and Exeter, to Southampton and Portsmouth, to Reading, Windsor and London," said Transport Secretary Chris Grayling.
"We are delivering the biggest rail modernisation programme for over a century and this franchise will deliver real changes for passengers, who can look forward to modern trains, faster journeys and a more reliable service."
But RMT union general secretary Mick Cash warned that the Chinese state was "set to make a killing at the British taxpayers' expense".
"The nonsense is that with the government triggering Article 50 this week they would be free to ignore EU rail directives that slam a block on public ownership," he said.
"It is frankly ludicrous that the Tories are continuing with the 'any state but the British state' policy which has plundered our railways for over two decades.
"RMT is deeply concerned at exactly what this announcement will mean for our members, these crucial rail services and the safety of the travelling public.
"We will be seeking an early meeting with the new owners to secure cast iron guarantees on the jobs and role of the guards, the future of the wider workforce and the safety and quality of passenger services."