King Wen of Zhou
Bi Xian was born in 802, during the reign of Emperor Dezong. His family was originally from Yun Prefecture (鄆州, in modern Tai'an, Shandong) and originally claimed ancestry from Ji Gao (), a son of King Wen of Zhou, who was created the Lord of Bi, although his traceable ancestry only went back to his fifth-generation ancestor, Bi Jing (), who served as a prefectural prefect during Tang Dynasty. Bi Xian's grandfather Bi Jun () served as a prefectural secretary general, while his father Bi Yun () served as a musical scholar in the ministry of worship.