Liu Hongcao (, , died 938) was an imperial prince of the Chinese Five Dynasties and Ten Kingdoms Period state Southern Han.
He was the ninth son of emperor Liu Yan and received the title of Prince of Wan (èÂÂ) in 932.
In 937, Dðáng ÃÂình Nghá»Â, the ruler of Ténh Hải quân, was killed by his general Kiá»Âu Công Tiá» n. Ngô Quyá»Ân, who was Nghá»Â's son-in-law, mobilized his army against Tiá» n. Tiá» n requested help from Southern Han. Liu Yan decided to annex Ténh Hải quân, so he granted Liu Hongcao the title Prince of Jiao (交çÂÂ, Giao vðáng, "Prince of Giao Chá»Â"), and dispatched him to Vietnam. Liu Yan himself commanded a follow-up army. In the next year, the army of Southern Han was defeated by Ngô Quyá»Ân in Bạch ÃÂằng River, and Hongcao was killed in the battlefield. Hearing the news, Liu Yan cried bitterly and withdrew his own fleet.