House church pastor Yang Hua, who has been detained since December 2015, was sentenced to two and a half years in prison by a court in Guizhou province on Thursday.
The Communist Party has taken a hard line on Christianity since Chairman Mao came to power in 1949.
Mao threw more than 10,000 missionaries out of China at the start of his reign.
The party seized church property and killed or imprisoned Chinese Christians.
Now, Christians only have the right to worship at state-controlled churches.
Many choose to worship in house churches instead. Christians still face prejudice and even imprisonment for their beliefs.
According to human rights watchdog China Aid, Yang was found guilty of "divulging state secrets" at a secret trial which began on 28 December 2016.
He was detained by authorities more than a year ago after a raid of the house church where he served as pastor.
Yang had attempted to stop police from removing a hard drive from the church.
At the trial, Yang's lawyers claimed that the pastor had been tortured in prison by the government appointed prosecution.
Yang's wife and members of the public were not allowed to attend the trial.
"This is nothing but purely barbaric religious persecution," said Bob Fu, president and founder of China Aid.
"We urge President Obama and president-elect Trump to unequivocally condemn this brutal act."
In a letter written to his wife from prison in June last year, Yang wrote: "God is omniscient.
"I believe that he never makes a mistake... Let's pray and leave other things to God. Thank you for investing everything in this family.
"I am grateful for what God has given me; let's carry the cross and hasten down the road to heaven, until the day we meet the Lord."