Chapter 4 tackles the mystery about Kondratiev Wave, which falls into my research scope (Wang Zhan, “Cyclical Prosperity and Economic Prospects for the Pacific Rim,” Jianghuai Tribune, 1990 (3)). We should not only study the long economic cycle of about fifty years, but also look into relationship between Kondratiev’s theory of long cycle and the short-term business cycle as well as the relationship between the long cycle and social change, war and peace, and political change, which will help us to grasp the law of economic development. Section 1 discusses the relationship between Kondratiev’s theory of long cycle and the scientific and technological revolution, and the relevance between the two can reach 80%, but why not 100%? We can solve a lot of problems by drawing on relevant special cases. Section 2 analyzes the relationship between Kondratiev’s theory of long cycle and the world economy and politics, and provides regular clues for readers from different professional backgrounds to study politics and social change from this angle. Section 3 examines the relationship between Kondratiev’s theory of long cycle and China, reviews the economic and social changes of China in the long cycle, analyzes the drivers of contemporary economic growth in China, and puts forward the question on how to maintain economic growth.