Jigme Guri, 50, was released Wednesday evening from a prison in the Chinese province of Gansu and was accompanied to his hometown by the secret police, the organisation told Efe news.
Guri, also known as Labrang Jigme and Jigme Gyatso, was set free two months after he completed his sentence but authorities threatened him with consequences if he published any photo or video and forbade his family from hosting any welcome ceremony according to Tibetan traditions.
The monk is part of the Labrang monastery, one of the most important centres of Tibetan Buddhism.
"Labrang Monastery was one of the key points where Tibetan Buddhist monks participated in protests against the disastrous policies of China in Tibet," Passang Tsering, president of the Tibetan community in UK told Efe news.
Labrang was also part of some of the most critical protests against Beijing in Lhasa in 2008.
While Passang expressed joy at Guri's release, he also denounced his imprisonment by the Chinese authorities for exercising freedom of expression, a basic human right.
After one of these arrests, which lasted 42 days without any charges being presented against him, Guri alleged in a video online that he had been tortured.
"The way in which they repress and kill Tibetans (...) It stunned me. Telling us that Tibetans can be killed and our lifeless bodies thrown into the garbage with no one ever knowing why... They do not even treat us like dogs or pigs," Guri, who was convicted after a trial in which he was represented by tax lawyers of the government, had said.
According to a Human Rights Watch (HRW) report earlier this year, Chinese repression in Tibetan areas has spread from cities to rural areas and have targeted not just monks but also singers, writers and environmental activists.
According to HRW, the government has imposed unprecedented surveillance and control in rural areas and small towns leading to a sharp rise in arrests and protests.