She was the only child of Chieftain elder son Pomda Gonor of the Lemdha clan, of the Phomda Tsang line.

[1] Pachen took refuge in the Dharma when she was 8 years old and was subsequently initiated into the deity practice of Dorje Phurba, a Nyingma tradition.

In 1954, Pachen and her mother spent 6 months in Gyalsay Rinpoche's monastery, during which she completed Ngondro, or preliminary religious training.

[1] After news of eminent Chinese attack, Pachen returned to Lemdha to warn her family and gather their valuables.

After rejoining the earlier Lemdha resistance fighters, Pachen aided in dividing the refugees into smaller, less visible groups, organized and dispatched defensive patrols, and actively engaged in armed warfare.

Their camp was attacked by overwhelming Chinese forces in the area around the Pelbar village in Tingri County in late 1959, shortly after they heard of Chushi Gangdruk's defeat.

[1] Immediately after being captured, Pachen and her family were held in nearby abandoned houses that served as temporary prisons.

Soon after, many of the women, children and elderly people were released (including her mother, aunt, and grandmother), and Pachen was transferred to a 'collection center' in Lhodzong, where she was held for a month.

[1] Ani Pachen's autobiography, Sorrow Mountain: the Journey of a Tibetan Warrior Nun, was published in 2000, and she toured the United States and Europe.

In 2001, she visited the United Kingdom at the invitation of the Tibet Society, and led the annual march through central London to commemorate the Lhasa Uprising.