Abstract: Since the founding of the People's Republic of China (PRC) in 1949, Chinese society has undergone the first 30-year and the second 30-year development and changes, and are now striding forward on the journey of the new era. The state mainly pursued the revolutionary values of "ideal society construction" in the first 30-year and the utilitarian values of "priority to economic development" in the second 30-year, and is now pursuing the socialist core values of "living a better life" in the new era. In the 70 years after 1949, the evolution of social values is a history from affirmation to negation, and then to negation, which coincides with the theoretical logic of dialectical negation in Marxist philosophy. Analysis in terms of this coincidence between evolution of social values and theoretical logic not only helps to understand and grasp the social development and changes in PRC in the past 70 years, but also clarifies scientifically the necessity of cultivating and promoting socialist core values in the new era.