Sun Bu'er (Sun Pu-erh, Chinese: 孫不二), one of the Taoist Seven Masters of Quanzhen, lived c. 1119–1182 C.E. in the Shandong province of China. She was a wealthy woman and was married with three children. Her family name was Sun and her first name was Fuchun (富春), Bu'er being her name in religion. Her husband Ma Yu was a close disciple of Wang Chongyang. At the age of 51, she took up the study of the Tao and herself became a disciple of Wang Chongyang, serving as a Taoist priestess. She eventually left her home and traveled to the city of Luoyang where after twelve years of practice, at Fengxiangu cave, she attained the Tao and, it is said, became an immortal. Sun was a teacher with several disciples, and founded the Purity and Tranquility School (Qingjing Lineage), and wrote many poems.

Sun Bu'er was born (as Sun Fuchun) in 1119, in a small town located within the Ninghai district of Shandong. Her birth was thought to be the result of a dream her mother had near the time of conception. In the dream, her mother saw seven cranes near her courtyard; six of them flew away, and the seventh magically entered her mother's body through her breast. The crane is a symbol of immortality and is seen as the bird of longevity. After this dream, her mother intuitively knew that she would give birth to a divine being.

At a young age, Sun Bu'er was already exhibiting saintly characteristics. She was very intelligent, lived out the Tao through chants, poems, and practicing calligraphy, and she was devoted to the rites and rules of propriety. Sun Bu'er received literary education from her father (Sun Zhongjing), who was a literary scholar. In her teens, she married Ma Yu (Ma Danyang), and the couple had three sons together. Their lives would remain quiet until 1167, when Wang Chongyang's arrival changed their lives.

Wang Chongyang (1112–1170) began a career as a religious leader soon after hermetizing himself on a 100-day retreat. He began a new movement named "Complete Perfection". Sun Bu'er's husband, Ma Yu, became an eager follower of Wang. This relationship caused disruption in Sun Bu'er's family life. Sun became so angry with Wang's interference in her social role that she hoped he would starve to death during his retreat. He was still alive after 100 days, during which he had perfected his sainthood. This caused Sun Bu'er to recognize her religious calling. In order for her husband to pursue his divine path, she had to let him be free. She then decided to leave her family, which contradicted what was seen as her wifely duty. She then began her role in becoming one of the few women in the "Seven Perfected". This became a major statement in the conflict women undergo between their social role and their religious calling.

Sun Bu'er finally joined the "Seven Perfected" after being urged ten times by Wang to convert. Once formally part of the group, Sun Bu'er received her Taoist name, Bu'er. She became a Taoist nun of Complete Perfection Order and a resident of the Golden Lotus Hall, where she received the title, "Serene one of clarity and Tranquility". Sun Bu'er was then able to engage in advanced rituals. Some of these rituals consisted of conducting exorcism and acquiring spiritual powers.

Sun then moved west, where she fought rain, frost and bad terrain. She began following the Zhouyi cantong qi (Tally to the book of changes), which gave her instruction to practice her reversed breathing. She unblocked the orifices in her body, and refined the Qi (energy flow) in her three dantian (located between the eyebrows in the head, the heart and abdomen). She eventually attained full realization of the Tao.

Sun Bu'er then moved to Luoyang and attracted disciples. She set herself up in a residence called Feng xiangu dong (Grotto of the Immortal Lady Feng). She founded a female lineage there and became known for her eccentricity and for her ability to perform exorcisms.

Sun Bu'er did not appear among the Seven Perfected until sixty years after her death. She then received the formal title "Perfected of Clarity and Tranquility and Deep Perfection Who Follows Virtue".