Mobility is an important characteristic of an era of internet and globalization, and global city is a crucial platform for such mobility. The increasing mobility has caused a significant turn in social sciences. When mobility is regarded as normal rather than abnormal, it will definitely challenge the traditional conception of "society". The mobility of society, especially that of a global city brings new challenges in social governance. We should develop a novel view of governance and social imagination so as to build a responsive social governance framework.