Using Python tools, this paper analyzes the texts of speeches made by five generations of Chinese leaders: Mao Zedong, Deng Xiaoping, Jiang Zemin, Hu Jintao and Xi Jinping, and uses media records as auxiliary materials to analyze the characteristics of speeches made by Chinese leaders as well as the trend of evolution in terms of their stance and viewpoints, argumentation methods, linguistic features, rhetorical techniques, and speaking styles. Then this study applies historical analysis and discourse analysis to explain the reasons for the evolution of modern Chinese political speeches from 1949 to the present. It is found that personal factors such as place of birth, family situation, personality traits, educational experience, and work experience are important variables that affect the political speeches of each Chinese leader. In addition, historical structural changes have also influenced the evolution of political speeches in China, including the deepening of political institutionalization, rising educational level of society, rapid changes in media forms and communication efficacy, and the easing of China’s relations with capitalist countries.