Pastor Gu Yuese, also known as Joseph Gu, was the pastor of the state-sanctioned Chongyi Church in Zhejiang Province, one of the biggest in the country.
He was first detained between January and March 2016 before being released on bail for protesting at the state's demolition of church crosses.
Officials then sacked him from his role at the church.
Earlier this week it emerged he had been rearrested, this time charged with "misappropriation of funds," but authorities refused to provide any details.
Mervyn Thomas, Chief Executive of Christian Solidarity Worldwide (CSW) said: "It is not clear why Pastor Gu has been detained again. However, his re-arrest comes at a time of increasing restrictions on religious activities and organisations, including both registered and unregistered churches.
"Given that Pastor Gu was first detained in connection with his peaceful opposition to the removal of crosses from churches in Zhejiang, it appears this case is part of a trend of intolerance towards any expression of views contrary to the government's policies and actions.
"We call on the authorities to release Pastor Gu and to uphold the rights of freedom of religion or belief and expression in accordance with international law."
