Qian Yi was originally from Qiantang (now Hangzhou, Zhejiang). His great-grandfather settled in Yunzhou (now Dongping, Shandong). His maternal uncle, Lü, was also knowledgeable in medicine, and Qian Yi began studying medicine under Lü as he grew older. He first learned pediatric cranial techniques, specializing in pediatrics, which earned him great fame. During the Yuanfeng era (1078–1086), he was appointed as a medical official in the Hanlin Academy after curing the daughter of a princess. The following year, when the royal prince Yi Guo suffered from spasm and convulsion, and the royal physicians failed to treat him, Qian Yi was recommended by the princess and successfully treated the prince with "Oven Yellow Earth Decoction." He was then promoted to the position of Imperial Physician and granted a purple robe and a golden fish pouch. From then on, both high-ranking officials and common people sought Qian Yi for medical treatment. Qian Yi was overwhelmed with medical duties, leaving him almost no free days, and he soon resigned due to illness. Later, Emperor Zhezong summoned Qian Yi to the palace, where he stayed for a long time before eventually retiring due to illness. In his later years, he suffered from paralysis in his left limbs and passed away at home at the age of 82.

Qian Yi was erudite and knowledgeable. Although he was most renowned for pediatrics, he was skilled in treating various medical conditions. He did not rigidly adhere to ancient prescriptions but used medications flexibly and innovatively while maintaining his own principles. He authored Cold-Damage Disease: Subtle Indicators in five volumes and Discussions on Infants in one hundred chapters, but unfortunately, these works have been lost. His clinical experiences were compiled by his disciple Yan Xiaozhong into Xiao'er Yaozheng Zhijue in three volumes, which became an important treatise guiding the theory and practice of Chinese medicine in pediatrics.