Abstract: Based on the perspectives, theories, and methods of leadership science, this paper studies Mao Zedong's leadership thoughts and practices during the democratic period as a promising new research field. Mao Zedong's thoughts of leadership science are mainly embodied in seven aspects:leadership essence, leadership responsibilities, leadership system, leadership method, leadership art, leadership literacy, and leadership style, which has formed a complete theoretical system with rich content. It has four distinctive features:scientific nature, affinity to the people, practicality and predictability. This is still of great theoretical and practical value for improving the party's ruling ability and strengthening the construction of leading cadres in the new era.