The background and connotations of smart growth theories of America were introduced first,spatial expansion features of Nanjing City were summarized as the following 3 points:population growth,expansion of urban spaces and industrial expansion.And then problems emerged in the spatial expansion were pointed out as:A."Sprawl" in the urban development;B.Improper internal spatial structure of the city;C.Destructed historical and cultural context of the city.Smart growth theories were applied in this study to analyze potential problems in the spatial expansion of Nanjing,corresponding countermeasures were given as:defining proper growth boundaries,restricting total growth volume,saving land;strictly controlling growth intensity,fully utilizing resources,intensively using land;scientifically evaluating growth benefits,promoting recycling of resources,and realizing sustainable growth.By learning from overseas smart growth theories,the authors hoped to provide useful references for the overall land use planning and urban planning of Nanjing City.