Cao Xi was born in Pingling, Fufeng, Eastern Han Dynasty. The courtesy name is Zhongze. During the reign of Emperor Zhang of Han Dynasty, he was a secret scholar. The craftsman of seal script and official script is especially famous for the method of creating hanging needles and hanging dews. Jin Weiheng's "Shu Shi" says: "Cao Xi is good at seal script, which is slightly different from (Li) Si, and he is also said to be good. Dan Chun is the master." The Northern Wei Dynasty Jiangshi's "On Shu Biao" said that Cao Xi's seal script was "extremely exquisite in the Southern Dynasty Liang Dynasty" Yuan Ang's "Ancient and Modern Book Reviews" says: "Cao Xi's books are like a Taoist commentator on classics, which is outstanding. Zhang Huaijin of the Tang Dynasty wrote in the volume "Shu Duan": "Cao Xi's seal script and official script are famous all over the world." It is also said that Cao Xi "is good at hanging needles to expose the exposed surface, which was practiced by later generations. His small seal script and official script are of great quality." Zhang Huaiguan's "Shu Appraisal" lists Cao Xi's calligraphy as the first class, ranking with Handan Chun and Liu Desheng. Song Mengying's "Eighteen Styles" also says: "Hanging needles." The dew was made by Cao Xi. Those who use hanging needles to seal script are clumsy and have the edge of hanging needles. When the seal script is exposed, it is said that the decoration is like light dew. "
