Abstract：This thesis separately defines and compares three basic terms in the literature field: Ci, Ci Theory and the Discipline of Ci Theory. It is found that first originated in Tang Dynasty, with Convivial Music as its expression pattern, Ci is a unique form of Chinese poetry. Ci Theory, however, is a research especially on Ci. Found by Wang Guowei, developed by Long Yusheng and his peers, Ci Theory evolves into a systematic study. Even from the beginning Ci theory came hand in hand with Ci, the study of Ci Thoery has not become a discipline till modern time, to which Xia Chengtao, Tang Guizhang, Long Yusheng, Zhan Antai(Known as Four Masters in Ci field) contributed a lot.
