The 40-megawatt power plant has 160,000 panels resting on a lake that emerged after the collapse of a coal mine in central Anhui province.
It is part of Beijing's effort to wean itself off a fossil fuel dependency that has made it the world's top carbon emitter, with two-thirds of its electricity still fueled by coal.
The solar facility went online around the time of President Donald Trump's much-criticized June 2 decision to withdraw from the international accord aimed at saving the planet from climate change catastrophe.
His move shifted the spotlight on to China and whether it will take on the leadership mantle in the fight against global warming.
Days after his announcement - and by coincidence - Beijing hosted an international conference on clean energy. It was an opportunity for China, which already produces two-thirds of the world's solar panels, to boast of its commitment to accelerating investment and reforms for greater use of renewable energies.
"The US withdrawal from the Paris agreement offers China an unprecedented opportunity to take the lead in climate change," energy expert Frank Yu of Wood Mackenzie consultancy said.
The Beijing forum put a spotlight on efforts by Chinese authorities and companies to develop renewable energy.
China has been the world's largest investor in clean energy since 2012, spending US$88 billion (HK$686 billion) on wind and solar power last year.
California Governor Jerry Brown used the Beijing conference to seek partnerships with China on climate change.
China's solar capacity more than doubled in 2016. The official goal is for 20 percent of Chinese power consumption to come from low-emission energy, including nuclear, by 2030, compared to 11 percent currently.