The city will become the main way to update the city space development. Shenzhen city for the next ten years to update will involve 30% of the city's space, will have a far-reaching impact on the city population. The in reference to update in some cities at home and abroad on the basis of study on the impact of population, in Shenzhen has publicly 36 cities in the update project as samples, we adopted two kinds of methods of mathematical analysis and case study, comprehensive analysis the the possible impact on the total population, distribution and structure transformation. The conclusion is the current urban renewal mode cannot effectively achieve reduce the total number of population, population layout reasonable, but can quickly realize the transformation of population structure, population of gentleman will become inevitable. This paper proposed coordination mechanism set up city renewal and population development, population increase impact assessment in the project approval, to prevent the city update cause serious population problems of. <<