The UK will guarantee a £2bn deal with China, which will see investment in the Hinkley nuclear power plant and the possible construction of further reactors.
Chancellor George Osborne made the announcement during his visit to China and said the deal would pave the way for a final investment decision on the delayed project by French energy company EDF.
Speaking to the Financial Times, Energy Secretary Amber Rudd said she wanted Beijing to take the lead in developing new nuclear plants in Britain.
At a joint news conference with China's Vice-Premier Ma Kai, Mr Osborne said: "We want the UK to be China's best partner in the West. [This guarantee] paves the way for Chinese investment in UK nuclear [to help provide] secure, reliable, low carbon electricity for decades to come."