Mr Liu has been a political activist for more than two decades
Dozens of prominent Chinese academics have signed a petition calling for the release of veteran political activist Liu Xiaobo.
They say his arrest shows that no one in China has the right to publicly express their opinions.
Mr Liu was formally arrested on Tuesday - more than six months after he was detained by the authorities.
He has been charged with inciting subversion by spreading rumours and defaming the government.
Mr Liu, who is a writer, has spent more than two decades pushing for political reforms in China.
In the petition, the 52 signatories of the petition said his comments had been rational and constructive, and showed a sense of social responsibility.
It added: "Liu Xiaobo's troubles show the environment each of us must exist in.
"He cannot freely express his views, which means none of us can publicly and freely express our views."
Mr Liu was detained by the police last December, just before the publication of Charter 08, a document calling for political reforms.
His exact whereabouts were not known and his lawyer was not allowed to visit him.
Beijing's public security bureau ended speculation about Mr Liu's fate with the announcement earlier this week that he had been officially arrested.