This essay describes the opinion of Environmental Conservation of the Mind, the core values of the Integration of Tiantai Thought made by Master Sheng-Yan and discusses the specific content and practices. Master Sheng-Yan, the founder of Dharma Drum Mountain, regarded the mental environment as the main point. In order to realize the dream of improving the quality of life and construct a pure land on earth, which means all people in the world could live a healthy, joyful and peaceful life, Master Sheng-Yan was mainly aiming to purify society by helping people to purify their minds. He had said that he was really yearning for Unification with Compassion and Wisdom and Unification with śamatha-vipaśyanā, which were promoted by Tiantai school. The reason was that both doctrine and vipaśyanā play important roles, fulfilling separate but complementary needs, which was also a kind of spirit that Buddhism needs nowadays. The author will begin with the Tiantai school as the theme of studying the thought of Master Sheng-Yan. At the beginning of this essay, the author discusses the doctrinal classification of Buddhist teaching background of Master Sheng-Yan, tracing back the time which he promoted the construction of pure land on earth in the name of Tathagata-Garbha. After studying the Complete Works of the Drums written by Master Sheng-Yan, searching and analyzing the information, the author summarizes the meaning of Tiantai Thought in various representative works. Also, the author drafts the thread of thought, opinion and practice of Integration of Tiantai Thought in the research, and then describes and discusses the way which Master Sheng-Yan mixed the concept and methods of vipaśyanā into Environmental Protection of the Mind. Eventually, the author concludes the innovative concept and influence of Environmental Protection of the Mind made by Master Sheng-Yan and represents the new meaning of it.