Ai Weiwei, an outspoken critic of the Chinese Government, was arrested at Beijing airport on 3 April.
China has said the avant garde artist was being investigated for unspecified economic crimes. His lawyer and wife were originally denied access to him.
The Xinhua News Agency said on Wednesday he had been released on bail after confessing to tax evasion.
It said Ai Weiwei’s poor health was also a factor and that he had shown a “good attitude in confessing his crimes” and repeatedly pledged to pay back taxes he owed.
News of his release was welcomed by the sculptor Anish Kapoor, who called on the Chinese Authorities to give him a fair trial. But he urged the artistic community to keep up a boycott of China, adding: “while I am thankful that he has been released, I do not think that artists should present their work in China until the situation has been resolved.”
A collection of photos documenting the work by - and those in support of - Chinese artist Ai Weiwei: Ai Weiwei photo gallery
At the time of Ai Weiwei’s detention the British Foreign Secretary William Hague said: “I call on the Chinese Government to urgently clarify Ai’s situation and wellbeing, and hope he will be released immediately.”
His concerns were echoed by the US State Department: “We obviously continue to be deeply concerned by the trend of forced disappearances, extra-legal detentions, arrests and convictions of human rights activists for exercising their internationally recognised human right for freedom of expression.”
China’s Prime Minister, Wen Jiabao, is due to arrive in the UK this weekend at the start of an official visit to several european countries.
The Lisson Gallery, which represents the artist in the UK, said at the time of his arrest: “Ai Weiwei is one of the leading cultural figures of his generation and consistently displays great courage in placing himself at risk to affect social change through his art.
“He serves as an example for legitimate social criticism and free expression both in China and internationally.”