Cameron also pledged to put his "full political weight" behind a proposed EU-China trade agreement.
"Some in Europe and elsewhere see the world changing and want to shut China off behind a bamboo curtain of trade barriers. Britain wants to tear those barriers down," Cameron told reporters after arriving on a three day-visit with a high profile delegation of 100 business leaders and six cabinet ministers.
After talks with Cameron, Chinese Premier Li Keqiang said the pair had agreed to "push for breakthroughs" on nuclear power and high speed rail.
"On infrastructure, the two sides have agreed to push for breakthroughs and progress in co-operation on our enterprises in nuclear power and high-speed railway," he said.
More From This Section
Cameron's meeting with the exiled Tibetan spiritual leader Dalai Lama in 2012 was condemned by Beijing and led to a diplomatic stand off with China minimising all contact with the UK.
But after today's talks Britain has reaffirmed its respect for China's sovereignty and territorial integrity, adherence to the one-China policy and respect for China's core interests and major concerns, according to Li.
"Britain wants China to realise its dream and I believe we can help each other succeed in the global race. The Chinese side is willing to not only participate but also purchase equities and stocks in UK nuclear power projects, and the UK side is open to this idea," state-run Xinhua news agency quoted Cameron as saying.
Cameron promised to "champion an EU-China trade deal with as much determination as I am championing the EU-US trade deal".