 It is not known when Yuwen Shiji was born.He was a son of the Sui Dynasty general and official Yuwen Shu, and he had at least two older brothers, Yuwen Huaji and Yuwen Zhiji (宇文智及).During the reign of Sui's founder Emperor Wen, Yuwen Shiji was, on account of his father's contributions to Sui, created the Duke of Xincheng County (新城县公).