China has achieved great achievements since the reform and opening up, and meanwhile it has to face a series of newly unavoidable social conflicts. It is necessary to find the way to settle down how to properly handle the current social contradictions and ensure the development of the reform and opening up. Mao Zedong clarified the socialist fundamental contradiction, its nature and characteristics for the first time, and creatively put forward the concept and method to distinguish and deal with two different kinds of contradiction, which provided the guiding principles for the reform and opening up. As the representative of the second generation of the collective leadership of the Communist Party of China, Deng Xiaoping launched a new journey of reform and opening-up, which inherited and developed Mao Zedongs socialist fundamental contradiction theory in the theoretical origin. Currently, in the new historical period of building an all-round comparatively well-off society, it is necessary to adhere to the guidance of socialist fundamental contradiction theory to settle down the socialist basic contradiction by deepening the main socialist contradictions.