The existential trend of thought spread widely in Europe from the end of the 19th century to the middle of the 20th century and had far-reaching influence. As a philosophical trend that responded to the two world wars and the "retreat of God" and other events that had a great impact on human existence itself, of course it also originated from the deepest level of the Western philosophical tradition, existentialism. Faced with the "crisis of existence", it explores issues such as anxiety, death, boredom, human impersonality, and the experience of the death of God. These issues are not so commensurate with traditional Western philosophy, but they are indeed life issues closely related to people living in an era where suffering and worry are constantly eroding existence. After these questions were pondered and responded to by philosophers such as Kierkegaard, Nietzsche, Husserl, Jaspers, Heidegger, Gabriel Marcel, Camus, and Sartre, they converged into the existential trend of thought. This monograph by Professor Gao Zhangxuan carefully organizes and analyzes the existential trend of thought, and dedicates this book to his forefather, Mr. Xiong Wei, who made outstanding efforts to spread existentialism in China.