Different from those archetype world cities, e.g. New York, London and Tokyo, commanding andcontrolling center for world economy which rise naturally and spontaneously, the BRICS try to build their ownworld city through policy implanting which can be elaborated as transformation based on marketization andprivatization, namely take world city" as the strategic goal, and high-mobility infrastructure, effective urbanbest practices, industrial upgrading, and government reform as the specific policies. However, in the processof upgrading and transformation, the occupational structure, social stratification as well as spatial segregationincreasingly polarize. This inconsistency between the development of the megacities and the national economicdevelopment indicates that there are two paths for world city development, namely de-embedded from nationdirectly into the world economy or embedded" in nation which further lead to offshore" or onshore". Atpresent, the upgrading of mega-cities of the BRICS tend to be more onshore as these cities do not realize urbanautonomy based on the rule of law. So the BRICS mega-city development should consider the locality ,namelyinternal social factors and the urbanization stage, the former referring to unusual complexity while the latterreferring to the expanded poverty and informal employment as а result of large-scale immigration inflows. It isconcluded that the concept of emerging world cities, as policy design and implanting, will not be acclimatized",needs more rethinking in the sense of value, policy, path or other aspects.