Ruijin is a county-level city of Ganzhou in the mountains bordering Fujian Province in the south-eastern part of Jiangxi Province. Formerly a county, Ruijin became a county-level city on May 18, 1994.

The Ruijin Massacre was a series of massacres that took place in Ruijin and nearby counties in Jiangxi Province during the Chinese Cultural Revolution. From September 23 to early October, 1968, over 1,000 people were killed in the Ruijin Massacre; specifically, over 300 people were killed in Ruijin County, around 270 were killed in Xingguo County, and over 500 in Yudu County.