Abstract: Based on a four-year data of water depth in 1959, 1979, 2010 and 2013, the GIS technology is applied to study the variation of coastline, isobaths, and seabed profiles during the period of 54 years from 1959 to 2013 along the coast of Zhenhai, Ningbo. Moreover, the erosion deposition variation of the underwater slope is calculated. The results indicate that the coastline continuously moved seaward about 3-5 km, and 0 m, 3 m, 5 m isobaths generally moved seaward about 330-5 600 m in the 54 years. However, the movement rate of 0 m isobath was less than that of the coastline, resulting in a sharp shrink of the dry shoal. Accordingly, the deposition rate in the underwater slope is 0.46 cm/year from 1959 to 1979, 2.82 cm/year from 1979 to 2010, 14.14 cm/year from 2010 to 2013, illustrating that underwater slope experienced an adjustment process from basical stability to slightly deposition and then rapidly deposition. With the hydrological and sediment data of field observation, the deposition factors and trends were discussed. It is concluded that the large scale reclamation projects in the south coast of Hangzhou bay will maintain or even accelerate the deposition rate on the underwater slope.