Tue Trung Thuong Si was the Buddhist monk who contributed significantly to the integration of three Buddhist Zen sects Vo Ngon, Ti Ni and Thao Duong to form the Truc Lam (Bamboo Grove) school, a famous Buddhist Zen sect in the history of Buddhism in Vietnam. As the most prestigious Buddhist teacher of his time, Tue Trung Thuong Si had a profound influence on the formation of the ideology of Truc Lam Zen sect. So who is Tue Trung Thuong Si? The article proves that Tue Trung Thuong Si was Hung Ninh Vuong Tran Tung, the son of An Sinh Vuong Tran Lieu, the elder brother of Hung Dao Vuong Tran Quoc Tuan, and the uncle of Hung Nhuong Vuong Tran Quoc Tang who was thought to be Tue Trung Thuong Si. After the success of the resistance against the Mongols, Tran Tung became a Buddhist practitioner and called himself Tue Trung Thuong Si - the teacher of three masters of Truc Lam Zen sect. In the field of poetry, Tran Tung reached the excellent creativity, marking a new level of aesthetics in the Ly-Tran literary.