Dayun Expressway (pinyin: Dayun Gaosu Gonglu) is the largest expressway structure in China's Shanxi province.

It enters Shanxi as the Xuanda Expressway until approaching Datong (in northern Shanxi), becoming the Dayun Expressway afterwards. It ultimately ends at Rongcheng (in southern Shanxi).

The expressway passes through Datong, Shuozhou , Taiyuan, Lüliang , Jinzhong , Linfen , and Yuncheng . Thirty-one counties lie in its track.

It links with the Xuanda Expressway (heading toward Xuanhua and ultimately Beijing or Zhangjiakou), the Jiaofen Expressway (heading toward Fenyang ), the Yunfeng Expressway (heading toward Yongji and Fenglingdu ) and the Yunsan Expressway (heading toward Sanmenxia on the Yellow River).

The expressway passes through some interesting historical and scenic spots, such as Yanmen Pass , Mt. Wutai, the old city of Pingyao, as well as many temples.