The research by Harvard academics draws on leaked documents to paint a picture of the way China polices social media.
The government and its army of helpers write 488 million fake posts a year, the report said.
The profusion of comments on social media sits alongside other efforts, to find and delete content deemed too sensitive for Chinese citizens.
The vast majority of the comments and posts made on social media are crafted to look like they come from ordinary people, said the authors of the paper, who were led by Gary King from Harvard's department of government.
Many of the posts do not attempt to rebut or argue with critical commenters, they said.
"They do not step up to defend the government, its leaders, and their policies from criticism, no matter how vitriolic; indeed, they seem to avoid controversial issues entirely," said the paper.
"Letting an argument die, or changing the subject, usually works much better than picking an argument and getting someone's back up," it said.
More often Communist Party workers or ordinary citizens employed to post on behalf of the government engage in "cheerleading" about the state's achievements or its history.