River source culture is "Geography-Society" space culture of the origin of great rivers. In the study of Yellow River culture, river source culture has not received due attention. From the perspective of Chinese national community, the source culture of the Yellow River has characteristics of long-term, compound, radiation and transmission, and it has been promoting the formation of Chinese national community in its own evolution process. The following aspects can be considered as evidence: nomadic culture has gradually integrated into Chinese civilization and formed the bottom rhyme of Chinese civilization; ancient Qiang people played a vital role in the formation of Chinese nation, who brought many ethnic groups (especially Tibetans) into the big family of Chinese nation; common source, common culture and population migration across the Yellow River and the Yangtze River have connected civilization of the two great river as a whole. The holistic understanding of the source culture of the rivers will help to form shared historical and cultural memory of all ethnic groups and enhance consciousness of the Chinese national community.