Abstract: Exploitative intensity evaluation is the basis for potential and sustainable development of a bay, which can reflect the utilization level of the bay. It is of great significance to the economy development in bay area. The data resource is from 6 phases, in interval of 5 years, of TM/OLI remote sensing image in period of 1990 and 2015, from which we can get coastline and land utilization data of Hangzhou Bay, Xiangshan Bay and Sanmen Bay in areas of Ningbo. Base on the data, the paper makes a comprehensive analysis of the characteristics and the changes in three bays from two aspects, the coastline exploitation and development and land utilizations of the bays. The results show that firstly the artificialization of Ningbo bays has been intensified from 1990 to 2015. And the highest index of artificial coastline has moved from Xiangshan Bay (0.16) to Sanmen Bay (0.61). The artificialization degree in some parts of tideland has been weakened for the intensity of reclamation is weaker than the intensity of sediment deposition. Secondly, for a long period the utilization structures of coastline in Hangzhou Bay and Sanmen Bay of Ningbo have always been a monotonous main body structure while it has changed to binary or even multivariate structures in Xiangshan Bay. Thirdly, the intensity of land and coastline uses are increasing. Among them Xiangshan Bay has the highest intensity index of coastline utilization and it reaches 0.42. And index of land use degree finds its maximum (292.300) in Hangzhou Bay of Ningbo where it gets the strongest land use changes. Fourthly, the zone bit, resources endowment, social economy level and policy factors are important factors modifying the development and utilization of the three bays.