Abstract: According to the important spirit of the Central Conference on Work Relating to Ethnic Affairs,strengthening commonality should be an important direction for ethnic affairs in big cities.The surveys in Beijing,Shanghai and Shenzhen show that the interviewees have a high awareness of co-governance of public affairs,but less practice of jointly participating in the governance of public affairs;although the big cities have a high level of sharing the achievements of economic and social development,they have weak foundation for promoting common prosperity and development;in spite of multiple cultural activities with rich contents for ethnic minorities,conditions for jointly building a common spiritual home areinsufficient.And although there are many interactive carriers,the multi-directional embedding needs to be strengthened.All these reflect the basic situation of the construction of commonality of all ethnic groups in big cities.At the same time,factors influencing the enhancement of commonality of ethnic groups in these cities are still seen in the insufficient supply of public resources,the unbalanced allocation of production factors,the weak construction of shared culture,and the lack of integration methods of mutual embedded structure.At the present stage,taking details into consideration,we should enhance the commonality of all ethnic groups from the aspects of political,economic and cultural life,continuously forging a strong sense of community for the Chinese nation.

Key words: ethnic affairs, strengthening commonality, big cities, forging a strong sense of community for the Chinese nation, governance of public affairs