Abstract: The great founding spirit of Party building is a spiritual system rich in connotation and profound in meaning. To accurately grasp the great spirit of Party building，we should rationally understand its meaning in the three dimensions of theory，history and practice with profound thinking，broad historical vision and deep grasp of reality. From the theoretical dimension，the great founding spirit of Party building not only demonstrates the advanced nature of the CPC itself，but also embodies the theoretical characteristics of Marxist theory，and inherits the spiritual core of China's traditional culture. From the historical perspective，the great founding spirit of Party building has germinated in the historical process of “standing up” of the Chinese nation，and developed in the historical process of “getting rich” and “becoming stronger” of the Chinese nation. From the practical perspective，the great founding spirit of Party building guides the realization of the ”four Greats” of socialism with Chinese characteristics in the new era. Scientific understanding of the three dimensions of the great founding spirit of Party building is helpful to clarify “where the great spirit of Party building comes from” and “where to go”，and then promote the inheritance of the great spirit of Party building.

Key words: Xi Jinping, the Communist Party of China, great founding spirit of Party building, socialism with Chinese characteristics, the great rejuvenation of the Chinese nation