Cai Rukai, also known as Cai Zhigeng, was from Nanchang, Jiangxi Province. He was the Juren in Ding You of the reign of Qing Emperor Guangxu. He worked as Superintendent of Peiyang University from 1906 to December 1911 and was then promoted Head of Department of Education of Zhili (now Hebei Province). Since February 1913, he served as President of Peiyang University concurrently until taking the posts of Chief of Ministry of Education on February 25th, 1914. During his presidency, Peiyang University was renamed National Peiyang University. He served as the Tixueshi of Zhili in 1912, promoted as the Education Chief of Peiyang University and Provincial Governor of Shandong in 1913, and general manager of Jangxi Nanxun Raiway Company in his later years.