Abstract: The System of Selecting Officials by the Evaluation of the Candidates' Poems or Rhyming Proses was very special in ancient China. This paper discusses the causes of the system formation, which include such elements as: the tradition of the Confucian poetry education, the prosperity of poetry in the dynasty, the character of the rulers of the dynasty, the impact of social practice, the benefits of different political groups, and the uniqueness of the poetry.