A native of Qishui (present-day Xishui County, Hubei Province), he was born into a family of generations of physicians. From a young age, he was intelligent and studious, with a photographic memory for books. He studied the pulse texts of Huangdi and Bian Que, quickly mastering their theories and even developing new interpretations before he was 20 years old. Later, he suffered from seasonal diseases and deafness, which led him to delve deeper into medical texts such as Lingshu, Taisu, and Jiayi Jing. He also extensively studied various classical texts related to medicine, integrating and synthesizing their knowledge.

Pang An-shi was highly skilled in medicine, always prioritizing the urgent needs of his patients. He practiced medicine without seeking personal gain, often allowing patients to stay in his home for personal care until they were cured and sent home.

In his later years, he referenced various medical theories and combined them with his own experiences to write the Cold-Damage Disease General Treatise in six volumes, which supplemented and expanded on the ideas of Zhang Zhongjing. A notable feature of his work was his emphasis on explaining warm febrile diseases, advocating for the distinction between warm diseases and cold-damage diseases, which was a significant advancement in the study of external contraction diseases.

Pang held the Nan Jing in high regard and authored tens of thousands of words in the Nan Jing Discriminations, though unfortunately, this work has not survived. He also wrote the Main Responses Collection and Materia Medica Supplement, both of which have been lost.