King Huanhui of Han (Chinese: 韓桓惠王^[1][2]; pinyin: Hán Huánhuì Wáng; died 239 BC), personal name unknown, was a monarch of the Han state. He was the son of King Xi, whom he succeeded in 272 BC. During King Huanhui's reign, Han Fei submitted numerous proposals to enact Legalism.^[1] In 246 BC, King Huanhui sent Zheng Guo west to the Qin state to construct a canal with the intention of wasting Qin's resources. The canal came to be known as the Zheng Guo Canal.^[3]

In 262 BC, Qin sent Bai Qi to invade Han and took Yewang.^[1][4] To broker peace, King Huanhui ceded Shangdang Commandery to Qin. The people of Shangdang refused to be ruled by Qin but also lacked the military strength for defense. Shangdang's governor-general Feng Ting (馮亭) surrendered instead to the Zhao state. Zhao accepted the surrender and sent Lian Po to defend Changping; the Battle of Changping ensued.^[4]

King Huanhui died in 239 BC and was succeeded by his son, Han An.^[1][3]

• Shiji Chapter 45
• Zizhi Tongjian Volume 4, 5, 6