With the population growth and the rapid development of national economy, urban construction scale has also been growing. Urban expansion has led to a sharp reduction of arable land, which in turn seriously restricted the social and economic development. In this paper, adopting the remote sensing data and topographic map data acquired in different periods and using image processing and interpretation of human-machine interactive information retrieval method, the authors obtained the scale of urban development and land use change information of 10 different periods in Changsha. According to statistical analysis and data distribution, a mathematical model for urban growth in Changsha was established, and the factors responsible for helping and restricting the economic development in Changsha are analyzed and evaluated.