Abstract: "Momentous changes unseen in a century" is an important statement made by Chairman Xi Jinping by combing the evolutionary logic of world development dynamics in recent 100 years, analyzing the law of international development imbalance, and comparing the impact degree, spread range and influence degree of changes in the present and the past. Clarifying the background, theoretical connotation and specific performance of the "momentous change unseen in a century" is the fundamental basis for us to accurately grasp historical direction and formulate a good recipe of "China's governance" and "global governance". In order to triumph over the challenges and problems faced by the world in a century, China’s state leaders put forward a China Plan for building a community with a shared future for mankind. To create a more open new situation of a community with a shared future for mankind, following things are essential: to break through old tradition and construct a new governance model of a community with a shared future for mankind; to create new kinetic energy and construct innovation vitality of a community with a shared future for mankind; to enter a new stage and grasp the historical inevitability in constructing a community with a shared future for mankind; to master true ability and grasp scientific methodology in building a community with a shared future for mankind; to enhance new efficiency and give full play to China's advantages in building a community with a shared future for mankind.