Sun Bu'er's life before she entered formal Taoist practice gave little outward sign of what would follow. She was born into a prosperous family in Ninghai, Shandong, married to Ma Yu, and by most accounts occupied a comfortable domestic position as wife and mother of three children in a household wealthy enough to be locally notable. That changed in 1167, when the itinerant Taoist master Wang Chongyang arrived in Shandong and accepted Ma Yu as a disciple. Sun Bu'er, already in her fifties, chose to take up the practice alongside her husband rather than remain outside it, an unusual step for a woman of her age and social position in twelfth century China.
Accounts of her subsequent training describe a period of severe ascetic discipline: she is said to have left her household entirely, travelled to Luoyang, and spent roughly twelve years in isolated practice at a cave known as Fengxian, deliberately altering her appearance to travel and live unmolested as she pursued cultivation. Taoist hagiography credits this period with her attainment of the Tao and, in the tradition's own terms, her transformation into an immortal, the same status attributed to her six male companions among Wang Chongyang's core disciples.
What distinguishes Sun Bu'er's story from a straightforward hagiographic conversion narrative is the degree to which the historical record outside pure legend corroborates the shape of it: her existence as one of Wang Chongyang's seven principal disciples, her authorship of surviving poetry, and her founding of a distinct teaching lineage are treated by modern scholars of Taoism as considerably better attested than the miraculous elements layered onto her biography by later devotional writing.