In China, the last known prisoner to be held for taking part in the Tiananmen Square uprising is set to be released today.

He was one of 1,600 people jailed after a brutal military crackdown following the protests of June 1989, but little is known of him.

There is no photograph of Miao Deshun and he has had no contact with the outside world for years.

In 1997 he told his family not to visit anymore and for a while many believed he was dead.

But today, Beijing's Number one Intermediate People's Court has scheduled his release.

Routinely tortured and put in solitary confinement

Fellow Tiananmen activist Sun Liyong was his cellmate for seven years.

"We shared the same food — it was only fit for pigs and dogs," he said.

"He was a very quiet person and hardly spoke to anyone.

"And he refused to be reformed, to admit to any wrongdoing so he was put in solitary confinement for 10 or fifteen days every month."

In 1989, then 25-year-old Miao Deshun was sentenced to death for throwing a basket at a burning People's Liberation Army tank during the student-led demonstrations in Tiananmen Square. Two years later his sentence was commuted to life.

He is now getting an early release for good behaviour.

It is believed his sentence was much longer than most because he was a simple factory worker and not a student.

Sun Liyong said Miao Deshun was routinely tortured.

"He was often electrified, a four or five-man team would electrocute him together, I could hear screaming above me, he was shocked lots of times."

Tiananmen protestors 'changed the mindset of the people'

Sun Liyong, who runs a support group for Chinese political prisoners out of Sydney, said he could not see how Miao Deshun would survive on the outside.

He now suffers from chronic schizophrenia. In the early 2000s he was transferred to Yanqing, a prison for the mentally ill.

The 1989 Tiananmen Square pro-democracy student protests ended in a massacre by China's army. ( Reuters: Dominic Dudouble )

"I think he is mentally collapsed, he told his family in 1997 not to visit him anymore, probably because he didn't want to bring them troubles," Sun Liyong said about his former cellmate.

"I think his family have given up on him.

"The Communist Party may keep him somewhere, I don't know what they will do with him."

Miao Deshun's release will go unnoticed in China.

The Communist Party has effectively whitewashed the Tiananmen Massacre where hundreds were gunned down by the military.

Most in China do not know what happened.

One of China's most prominent dissidents Yang Jianli, who now lives in America, said the sacrifices they made have been worth it.

"Students stood up against government corruption, for freedom and democracy, they changed the mindset of the people," he said.

But Chinese President Xi Jinping is cracking down harder than ever on dissent, freedom of speech and human rights.

Yang Jianli said they were the darkest days since Tiananmen protests.

"Xi wants to continue communist rule forever so he is acting out of fear, not confidence," he said.