'Sea Dragon Castle') is a ruined fortress on the Longyan Mountain, in Hailongtun Village, Gaoping Town, Zunyi City, Guizhou Province, China.

It served as the stronghold of the Chiefdom of Bozhou, ruled by the Yang family, from the Southern Song to the Ming dynasty.

In the 28th year of the Wanli reign (1600), the Ming defeated the Bozhou rebellion, with the last tusi Yang Yinglong committing suicide and the castle was burned down.

The castle occupies a total area of 1.59 square kilometres (0.61 sq mi), with 6 eastern and 3 western passes and walls nearly 6 kilometres (3.7 mi) long.

Although there is nothing to support the tale, it is said that once a large stone wall, wide enough to allow horses to gallop on it, connected all of the passes.